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1

HALOACETIC ACIDS PERTURB PROTEIN PHOSPHORYLATION IN MOUSE EMBRYOS IN VITRO  

EPA Science Inventory

HALOACETIC ACIDS PERTURB PROTEIN PHOSPHORYLATION IN MOUSE EMBRYOS IN VITRO. MR Blanton and ES Hunter. Reproductive Toxicology Division, NHEERL, ORD, US EPA, RTP, NC, USA. Sponsor: JM Rogers. Haloacetic Acids (HAAs) formed during the disinfection process are present in drin...

2

GENOMIC ANALYSIS OF THE TESTICULAR TOXICITY OF HALOACETIC ACIDS  

EPA Science Inventory

Genomic analysis of the testicular toxicity of haloacetic acids David J. Dix and John C. Rockett Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, R...

3

COMPARATIVE PATHOGENESIS OF HALOACETIC ACID AND PROTEIN KINASE INHIBITOR EMBRYOTOXICITY IN MOUSE WHOLE EMBRYO CULTURE  

EPA Science Inventory

Comparative pathogenesis of haloacetic acid and protein kinase inhibitor embryotoxicity in mouse whole embryo culture. Ward KW, Rogers EH, Hunter ES 3rd. Curriculum in Toxicology, University of North Carolina at Chapel Hill, 27599-7270, USA. Haloacetic acids ...

4

Pregnancy loss and eye malformations in offspring of F344 rats following gestational exposure to mixtures of regulated trihalomethanes and haloacetic acids.  

PubMed

Chlorination of drinking water yields hundreds of disinfection by-products (DBPs). Among the DBPs, four trihalomethanes (THMs; chloroform, bromodichloromethane, chlorodibromomethane, bromoform) and five haloacetic acids (HAAs; chloroacetic, dichloroacetic, trichloroacetic, bromoacetic, and dibromoacetic acid) are U.S. EPA regulated. We assessed the combined toxicity of these DBPs. F344 rats were treated with mixtures of the four THMs (THM4), the five HAAs (HAA5), or nine DBPs (DBP9; THM4+HAA5). Mixtures were administered in 10% Alkamuls(®) EL-620 daily by gavage on gestation days 6-20. Litters were examined postnatally. All three mixtures caused pregnancy loss at ? 613 ?mol/kg/day. In surviving litters, resorption rates were increased in groups receiving HAA5 at 615 ?mol/kg/day and DBP9 at 307 ?mol/kg/day. HAA5 caused eye malformations (anophthalmia, microphthalmia) at ? 308 ?mol/kg/day. Thus, both HAAs and THMs contributed to DBP9-induced pregnancy loss. The presence of THMs in the full mixture, however, appeared to reduce the incidence of HAA-induced eye defects. PMID:20850520

Narotsky, Michael G; Best, Deborah S; McDonald, Anthony; Godin, Elizabeth A; Hunter, E Sidney; Simmons, Jane Ellen

2011-01-01

5

DETERMINATION OF NINE HALOACETIC ACIDS IN FINISHED DRINKING WATER  

EPA Science Inventory

Whenever natural water or humic substances are chlorinated significant concentrations of haloacetic acids (HAAS) are produced. he presence of HAAs in drinking water are suspected to have an adverse health effect on humans. o control HAAs in drinking water, analytical techniques s...

6

Sources and haloacetic acid/trihalomethane formation potentials of aquatic humic substances in the Wakarusa River and Clinton Lake near Lawrence, Kansas  

USGS Publications Warehouse

Gram quantities of aquatic humic substances (AHS) were extracted from the Wakarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentrations of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAA5) and trihalomethanes (THM4) that exceed U.S. Environmental Protection Agency (EPA) Maximum Contaminant Levels (MCL) in drinking water. AHS from the Wakarusa River and Clinton Lake originated from riparian forest vegetation, reflected respective effects of soil organic matter and aquatic algal/bacterial sources, and bore evidence of biological degradation and photodegradation. AHS from the Wakarusa River showed the effect of terrestrial sources, whereas Clinton Lake humicacid also reflected aquatic algal/bacterial sources. Greater amounts of carbon attributable to tannin-derived chemical structures may correspond with higher HAA5 and THM4 yields for Clinton Lake fulvic acid. Prior to appreciable leaf-fall from deciduous trees, the combined (humic and fulvic acid) THM4 formation potentials for the Wakarusa River approached the proposed EPA THM4 Stage I MCL of 80 ??g/L, and the combined THM4 formation potential for Clinton Lake slightly exceeded the proposed THM4 Stage II MCL of 40 ??g/L. Finally, AHS from Clinton Lake could account for most (>70%) of the THM4 concentrations in finished water from the Clinton Lake Water Treatment Plant based on September 23, 1996, THM4 results.Gram quantities of aquatic humic substances (AHS) were extracted from the Wakarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentrations of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAA5) and trihalomethanes (THM4) that exceed U.S. Environmental Protection Agency (EPA) Maximum Contaminant Levels (MCL) in drinking water. AHS from the Wakarusa River and Clinton Lake originated from riparian forest vegetation, reflected respective effects of soil organic matter and aquatic algal/bacterial sources, and bore evidence of biological degradation and photodegradation. AHS from the Wakarusa River showed the effect of terrestrial sources, whereas Clinton Lake humic acid also reflected aquatic algal/bacterial sources. Greater amounts of carbon attributable to tannin-derived chemical structures may correspond with higher HAA5 and THM4 yields for Clinton Lake fulvic acid. Prior to appreciable leaf-fall from deciduous trees, the combined (humic and fulvic acid) THM4 formation potentials for the Wakarusa River approached the proposed EPA THM4 Stage I MCL of 80 ??g/L, and the combined THM4 formation potential for Clinton Lake slightly exceeded the proposed THM4 Stage II MCL of 40 ??g/L. Finally, AHS from Clinton Lake could account for most (>70%) of the THM4 concentrations in finished water from the Clinton Lake Water Treatment Plant based on September 23, 1996, THM4 results.Gram quantities of aquatic humic substances were extracted from the Wakarusa River-Clinton Lake Reservoir system near Lawrence, KS, and concentrations of dissolved organic carbon (DOC) and the proportions of DOC accountable as aquatic humic substances were determined. In addition, the sources of the aquatic humic substances were defined, and the haloacetic acids/trihalomethanes formation potentials were assessed. The samples were collected over the period September 10-October 10, before any appreciable leaf-fall occurred from deciduous trees. Results showed that the humic substances produced considerable yields of haloacetic acids and trihalomethanes, with higher yields noted for fulvic acid from Clinton Lake. The aquatic humic substances were derived from sources outside and within the Wakarusa River and Clinton Lake and could yield sufficient trih

Pomes, M.L.; Larive, C.K.; Thurman, E.M.; Green, W.R.; Orem, W.H.; Rostad, C.E.; Coplen, T.B.; Cutak, B.J.; Dixon, A.M.

2000-01-01

7

Haloacetic acids content of fruit juices and soft drinks.  

PubMed

Water used in a food factory is frequently disinfected with chlorine, which originates disinfection by-products: haloacetic acids (HAAs) make up the second most prevalent class of these products. In this paper we propose the first static HS-GC-MS method developed for direct HAA determination in beverages; the method has higher sensitivity, simplicity and reliability than the only alternative available in the literature. From 150 beverages analysed, it is possible to conclude that at least 2 HAAs (dichloro- and trichloroacetic acids, DCAA and TCAA) are always present in beverages prepared with treated water, which remains constant for 2 or 3 months in the beverages. Moreover, beverages of 100% fruit juices and soft drinks prepared with mineral water (free of HAAs) do not contain any HAA at significant values. Therefore, DCAA and TCAA may indicate of the presence of treated water in beverages. PMID:25466077

Cardador, María José; Gallego, Mercedes

2015-04-15

8

METABOLISM, MICROFLORA EFFECTS, AND GENOTOXICITY IN HALOACETIC ACID-TREATED CULTURES OF RAT CECAL MICROBIOTA  

EPA Science Inventory

Haloacetic acids are by-products of drinking water disinfection. Several compounds in this class are genotoxic and have been identified as rodent hepatocarcinogens. Enzymes produced by the normal intestinal bacteria can transform some promutagens and procarcinogens to their bio...

9

Nine and Ten chemical haloacetic acid mixtures exhibit concentration-dependent departure from dose additivity  

EPA Science Inventory

Disinfection of water greatly decreases waterborne disease. Disinfection byproducts (DBPs), including haloacetic acids (HAAs), are formed when oxidizing disinfectants react with inorganic and organic matter in water. Water providers routinely assay for 9 HAAs in finished drinking...

10

Environmentally Realistic Mixtures of Haloacetic Acids Exhibit Concentration-Dependent Departures from Dose Additivity  

EPA Science Inventory

Disinfection byproducts (DBPs), including haloacetic acids (HAAs), are formed when oxidizing disinfectants react with inorganic and organic matter in water. Drinking water is assayed routinely for 9 HAAs (HAA9): chloro-, dichloro-, trichloro-, bromo-, dibromo-, tribrorno-, bromoc...

11

Amino Acids as Precursors of Trihalomethane and Haloacetic Acid Formation During Chlorination  

Microsoft Academic Search

Twenty amino acids were chlorinated and examined for the formation of trihalomethane (THM) and haloacetic acid (HAA). The\\u000a amino acids exhibited a high Cl2 demand (3.4–10 mg Cl2 mg–1 C) but low THM formation (?1 C) except for tryptophan and tyrosine (45.8 ? 147 ?g mg?1 C). Large variation in HAA yield occurred among the amino acids (from not detectable to 106 ?g mg?1

H. C. Hong; M. H. Wong; Y. Liang

2009-01-01

12

Determination of trace levels of haloacetic acids and perchlorate in drinking water by ion chromatography with direct injection  

Microsoft Academic Search

Disinfection by products of haloacetic acids and perchlorate pose significant health risks, even at low ?g\\/l levels in drinking water. A new method for the simultaneous determination of nine haloacetic acids (HAAs) and perchlorate as well as some common anions in one run with ion chromatography was developed. The HAAs tested included mono-, di-, trichloroacetic acids, mono, di-, tribromoacetic acids,

Yongjian Liu; Shifen Mou

2003-01-01

13

Haloacetic acids in the aquatic environment. Part I: macrophyte toxicity.  

PubMed

Haloacetic acids (HAAs) are contaminants of aquatic ecosystems with numerous sources, both anthropogenic and natural. The toxicity of HAAs to aquatic plants is generally uncharacterized. Laboratory tests were conducted with three macrophytes (Lemna gibba, Myriophyllum sibiricum and Myriophyllum spicatum) to assess the toxicity of five HAAs. Myriophyllum spp. has been proposed as required test species for pesticide registration in North America, but few studies have been conducted under standard test conditions. The HAAs in the present experiments were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). MCA was the most toxic to Myriophyllum spp. with EC50 values ranging from 8 to 12.4 mg/l depending on the endpoint, followed by DCA (EC50 range 62-722.5 mg/l), TCA (EC50 range 49.5-1702.6 mg/l), CDFA (EC50 range 105.3 to >10,000 mg/l) and with TFA (EC50 range 222.1 to 10,000 mg/l) the least toxic. Generally, L. gibba was less sensitive to HAA toxicity than Myriophyllum spp., with the difference in toxicity between them approximately threefold. The range of toxicity within Myriophyllum spp. was normally less than twofold. Statistically, plant length and node number were the most sensitive endpoints as they had the lowest observed coefficients of variation, but they were not the most sensitive to HAA toxicity. Toxicological sensitivity of endpoints varied depending on the measure of effect chosen and the HAA, with morphological endpoints usually an order of magnitude more sensitive than pigments for all plant species. Overall, mass and root measures tended to be the most sensitive indicators of HAA toxicity. The data from this paper were subsequently used in an ecological risk assessment for HAAs and aquatic plants. The assessment found HAAs to be of low risk to aquatic macrophytes and the results are described in the second manuscript of this series. PMID:15182970

Hanson, Mark L; Solomon, Keith R

2004-08-01

14

Mammalian Cell Cytotoxicity and Genotoxicity of the Haloacetic Acids, A Major Class of Drinking Water Disinfection By-Products  

EPA Science Inventory

The haloacetic acids (HAAs) are disinfection by-products (DBPs) that are formed during the disinfection of drinking water, wastewaters and recreational pool waters. Currently, five HAAs [bromoacetic acid (BAA), dibromoacetic acid (DBAA), chloroacetic acid (CAA), dichloroacetic ac...

15

Chlorine residuals and haloacetic acid reduction in rapid sand filtration.  

PubMed

It is quite rare to find biodegradation in rapid sand filtration for drinking water treatment. This might be due to frequent backwashes and low substrate levels. High chlorine concentrations may inhibit biofilm development, especially for plants with pre-chlorination. However, in tropical or subtropical regions, bioactivity on the sand surface may be quite significant due to high biofilm development--a result of year-round high temperature. The objective of this study is to explore the correlation between biodegradation and chlorine concentration in rapid sand filters, especially for the water treatment plants that practise pre-chlorination. In this study, haloacetic acid (HAA) biodegradation was found in conventional rapid sand filters practising pre-chlorination. Laboratory column studies and field investigations were conducted to explore the association between the biodegradation of HAAs and chlorine concentrations. The results showed that chlorine residual was an important factor that alters bioactivity development. A model based on filter influent and effluent chlorine was developed for determining threshold chlorine for biodegradation. From the model, a temperature independent chlorine concentration threshold (Cl(threshold)) for biodegradation was estimated at 0.46-0.5mgL(-1). The results imply that conventional filters with adequate control could be conducive to bioactivity, resulting in lower HAA concentrations. Optimizing biodegradable disinfection by-product removal in conventional rapid sand filter could be achieved with minor variation and a lower-than-Cl(threshold) influent chlorine concentration. Bacteria isolation was also carried out, successfully identifying several HAA degraders. These degraders are very commonly seen in drinking water systems and can be speculated as the main contributor of HAA loss. PMID:21974919

Chuang, Yi-Hsueh; Wang, Gen-Shuch; Tung, Hsin-hsin

2011-11-01

16

BROMOCHLORO-HALOACETIC ACIDS: EFFECTS ON MOUSE EMBRYOS IN VITRO AND QSAR CONSIDERATIONS  

EPA Science Inventory

The haloacetic acids (HAA) are a family of chemicals that are drinking water disinfection byproducts. We previously reported that bromo- and chloro-acetic acids altered embryonic development when mouse conceptuses were directly exposed to these xenobiotics in whole embryo culture...

17

HALOACETIC ACIDS AND KINASE INHIBITORS PERTURB MOUSE NEURAL CREST CELLS IN VITRO  

EPA Science Inventory

HUNTER, E.S.1, J. SMITH2, J. ANDREWS1. 1 Reproductive Toxicology Division, NHEERL, US EPA, Research Triangle Park and 2 Department of Cell and Developmental Biology, UNC-CH, Chapel Hill, North Carolina. Haloacetic acids and kinase inhibitors perturb mouse neural crest cells in vi...

18

TECHNIQUES AND METHODS FOR THE DETERMINATION OF HALOACETIC ACIDS IN POTABLE WATER  

EPA Science Inventory

Haloethanoic (haloacetic) acids (HAAs) are formed as disinfection byproducts (DBPs) during the chlorination of natural water to make it fit for consumption. Sundry analytical techniques have been applied in order to determine the concentrations of the HAAs in potable water suppli...

19

Determination of bromate and chlorinated haloacetic acids in bottled drinking water with chromatographic methods  

Microsoft Academic Search

Disinfection by-products of interest such as bromate, chlorate and chlorinated haloacetic acids in 10 representative brands of bottled drinking water were investigated with ion chromatography. With the developed method, the detection limits of the disinfection by-products were in sub-?gl?1 level. It was observed that bromate, chlorate and dichloroacetic acid could be detected in some water samples. In the bottled natural

Yongjian Liu; Shifen Mou

2004-01-01

20

Improving methodological aspects of the analysis of five regulated haloacetic acids in water samples by solid-phase extraction, ion-pair liquid chromatography and electrospray tandem mass spectrometry.  

PubMed

Haloacetic acids (HAAs) are organic pollutants originated from the drinking water disinfection process, which ought to be controlled and minimized. In this work a method for monitoring haloacetic acids (HAAs) in water samples is proposed, which can be used in quality control laboratories using the techniques most frequently available. Among its main advantages we may highlight its automated character, including minimal steps of sample preparation, and above all, its improved selectivity and sensitivity in the analysis of real samples. Five haloacetic acids (HAA5) were analyzed using solid-phase extraction (SPE) combined with ion-pair liquid chromatography and tandem mass spectrometry. For the optimization of the chromatographic separation, two amines (triethylamine, TEA and dibutylamine, DBA) as ion pair reagents were compared, and a better selectivity and sensitivity was obtained using DBA, especially for monohaloacetic acids. SPE conditions were optimized using different polymeric adsorbents. The electrospray source parameters were studied for maximum precursor ion accumulation, while the collision cell energy of the triple quadrupole mass spectrometer was adjusted for optimum fragmentation. Precursor ions detected were deprotonated, dimeric and decarboxylated ions. The major product ions formed were: ionized halogen atom (chloride and bromide) and decarboxylated ions. After enrichment of the HAAs in Lichrolut EN adsorbent, the limits of detection obtained by LC-MS/MS analysis (between 0.04 and 0.3 ng mL(-1)) were comparable to those obtained by GC-MS after derivatization. Linearity with good correlation coefficients was obtained over two orders of magnitude irrespective of the compound. Adequate recoveries were achieved (60-102%), and the repeatability and intermediate precision were in the range of 2.4-6.6% and 3.8-14.8%, respectively. In order to demonstrate the usefulness of the method for routine HAAs monitoring, different types of water samples were analyzed. In swimming pool water samples the ?HAAs were determined between 76 and 154 ng mL(-1). PMID:22608419

Prieto-Blanco, M C; Alpendurada, M F; López-Mahía, P; Muniategui-Lorenzo, S; Prada-Rodríguez, D; Machado, S; Gonçalves, C

2012-05-30

21

Effects Of Haloacetic Acid Mixtures in a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) Assay  

EPA Science Inventory

The haloacetic acids (HAAs) are a class of chemicals produced as byproducts of drinking water disinfection. Source water characteristics (such as level of bromide) affects which HAAs are present in drinking water and their concentration. For example, high bromide-source water wil...

22

Environmentally Realistic Mixtures of the Five Regulated Haloacetic Acids Exhibit Concentration-Dependent Departures from Dose Additivity  

EPA Science Inventory

Disinfection of water decreases waterborne disease. Disinfection byproducts (DBPs) are formed by the reaction of oxidizing disinfectants with inorganic and organic materials in the source water. The U.S. EPA regulates five haloacetic acid (HAA) DBPs as a mixture. The objective ...

23

Monthly variations of haloacetic acids in drinking water by GC/MS  

SciTech Connect

In a national survey of 53 drinking water plants in Canada, haloacetic acids (HAA) were identified as major disinfection by-products (DBPs) and were found in all the chlorinated drinking water supplies examined. The HAA levels were observed to vary with season (summer and winter), water treatment practice (chlorination, chloramination and ozonation) and distance from the treatment plant. In an effort to understand better the dynamics of HAA formation, three drinking water plants that used different disinfectant combinations (chlorine - chlorine, chlorine chloramine and ozone - chlorine) were studied each month (over a period of I year, 1994) at five locations within each supply system. Three HAA (mono-(MCAA), di-(DCAA) and tri-(TCAA) chloroacetic acids) were monitored in the present study, however, MCAA were consistently found at lower levels than DCAA and TCAA; only the DCAA and TCAA results are presented here.

Benoit, F.M.; Williams, D.T.; LeBel, G.L. [Environmental Health Directorate, Ottawa (Canada)

1995-12-31

24

Association between haloacetic acid degradation and heterotrophic bacteria in water distribution systems.  

PubMed

The occurrences of trihalomethanes (THMs), haloacetic acids (HAAs) and heterotrophic bacteria were monitored in five small water systems over a nine-month period to investigate the association between HAA degradation and heterotrophic bacteria populations. The sampling sites were chosen to cover the entire distribution network for each system. An inverse association between heterotrophic bacteria and HAA concentrations was found at some locations where chlorine residuals were around or less than 0.3mgL(-1). At other sample locations, where chlorine residuals were higher (over 0.7mgL(-1)), no HAA reduction was observed. A high heterotrophic bacteria count accompanied with a low chlorine residual could be used as an indicator for HAA degradation in distribution systems. PMID:19070347

Tung, Hsin-Hsin; Xie, Yuefeng F

2009-03-01

25

Pregnancy loss and eye malformations in offspring of F344 rats following gestational exposure to mixtures of regulated trihalomethanes and haloacetic acids  

EPA Science Inventory

Chlorination of drinking water results in the formation of hundreds of disinfection byproducts (DBPs), the most prevalent are trihalomethanes (THMs) and haloacetic acids (HAAs). Four THMs (chloroform, bromodichloromethane, chlorodibromomethane, bromoform) and five HAAs (chloroac...

26

Eco-friendly microextraction method for the quantitative speciation of 13 haloacetic acids in water.  

PubMed

This paper describes the first micro liquid-liquid extraction (MLLE) gas chromatography-mass spectrometry (GC-MS) method for the speciation of emerging iodinated acetic acids, along with conventional chlorinated and brominated acids in water. The haloacetic acids (HAAs) were derivatised using 3 reagents for their methylation, both in aqueous and organic media. The acidic methanol derivatisation in aqueous medium provided the best efficiency, requiring minimal sample manipulation. The derivatisation yield was improved through the use of microwave energy that drastically reduced reaction time (2 min). The HAA methyl esters were finally extracted using 250 ?L of methyl tert-butyl ether. This MLLE combined with the use of a large-volume sample injection coupled to a programmed temperature vaporiser-GC-MS improved the sensitivity of the method and minimised the generation of hazardous residues in accordance with the principles of "Green Chemistry". Detection and quantification limits (excepting tribromoacetic acid) within the range of 0.01-0.15 ?g/L and 0.03-0.5 ?g/L, respectively, were obtained and the relative standard deviation was lower than 10%. The eco-friendly method was applied to the speciation of the 13 HAAs in treated (chlorinated and chloraminated water) and untreated water. Up to 8 HAAs were found at detectable levels in treated water. The highly toxic monoiodoacetic acid was detected in almost all the chloraminated water. PMID:24679411

Cardador, María José; Gallego, Mercedes

2014-05-01

27

Haloacetic acids in the aquatic environment. Part II: ecological risk assessment.  

PubMed

Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC10). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs. PMID:15182971

Hanson, Mark L; Solomon, Keith R

2004-08-01

28

Effect of the chlorinated washing of minimally processed vegetables on the generation of haloacetic acids.  

PubMed

Chlorine solutions are usually used to sanitize fruit and vegetables in the fresh-cut industry due to their efficacy, low cost, and simple use. However, disinfection byproducts such as haloacetic acids (HAAs) can be formed during this process, which can remain on minimally processed vegetables (MPVs). These compounds are toxic and/or carcinogenic and have been associated with human health risks; therefore, the U.S. Environmental Protection Agency has set a maximum contaminant level for five HAAs at 60 ?g/L in drinking water. This paper describes the first method to determine the nine HAAs that can be present in MPV samples, with static headspace coupled with gas chromatography-mass spectrometry where the leaching and derivatization of the HAAs are carried out in a single step. The proposed method is sensitive, with limits of detection between 0.1 and 2.4 ?g/kg and an average relative standard deviation of ?8%. From the samples analyzed, we can conclude that about 23% of them contain at least two HAAs (<0.4-24 ?g/kg), which showed that these compounds are formed during washing and then remain on the final product. PMID:22747435

Cardador, Maria Jose; Gallego, Mercedes

2012-07-25

29

A fully-automated analyzer for determining haloacetic acid concentrations in drinking water.  

PubMed

A fully-automated, on-line, real-time analyzer has been developed for preconcentration and analysis of haloacetic acids (HAAs). Preconcentration of HAAs is achieved by sample acidification and solid phase extraction onto a hydrophobic polymeric resin using sequential injection analysis (SIA). The HAAs preconcentrate is then analyzed using post-column reaction-ion chromatography (PCR-IC), which is selective for HAAs. Systematic optimization of SIA preconcentration parameters are described followed by detailed method detection limit (MDL), accuracy, precision, and linearity studies. MDL values for the individual HAA9 species range from 0.4 to 0.9 ?g L(-1). Side-by-side comparison studies of HAAs analysis in 14 real-world drinking water samples from Alabama, Arkansas, Kentucky, Minnesota, Missouri, Mississippi, New York, Pennsylvania and Tennessee are presented that compare the optimized SIA-PCR-IC to USEPA Method 552.3. Trace levels of HAAs detected in select samples are reported, and the bias values calculated between the two methods are typically less than 5 ?g L(-1) for eight of the nine individual HAAs. PMID:25303464

Henson, Christina M; Emmert, Gary L; Simone, Paul S

2014-12-01

30

Comparison of three-dimensional fluorescence analysis methods for predicting formation of trihalomethanes and haloacetic acids.  

PubMed

This work investigated the application of several fluorescence excitation-emission matrix analysis methods as natural organic matter (NOM) indicators for use in predicting the formation of trihalomethanes (THMs) and haloacetic acids (HAAs). Waters from four different sources (two rivers and two lakes) were subjected to jar testing followed by 24hr disinfection by-product formation tests using chlorine. NOM was quantified using three common measures: dissolved organic carbon, ultraviolet absorbance at 254nm, and specific ultraviolet absorbance as well as by principal component analysis, peak picking, and parallel factor analysis of fluorescence spectra. Based on multi-linear modeling of THMs and HAAs, principle component (PC) scores resulted in the lowest mean squared prediction error of cross-folded test sets (THMs: 43.7 (?g/L)(2), HAAs: 233.3 (?g/L)(2)). Inclusion of principle components representative of protein-like material significantly decreased prediction error for both THMs and HAAs. Parallel factor analysis did not identify a protein-like component and resulted in prediction errors similar to traditional NOM surrogates as well as fluorescence peak picking. These results support the value of fluorescence excitation-emission matrix-principal component analysis as a suitable NOM indicator in predicting the formation of THMs and HAAs for the water sources studied. PMID:25597674

Peleato, Nicolás M; Andrews, Robert C

2015-01-01

31

Formation of haloacetic acids from dissolved organic matter fractions during chloramination.  

PubMed

The objective of this study was to investigate the roles of dissolved organic matter (DOM) fractions, pH and bromide concentration in the formation of haloacetic acids (HAA) during chloramination. DOM from two surface waters with a low (2.9 L/mg-m) and high (5.1 L/mg-m) specific UV absorbance (SUVA(254)) values was isolated and fractionated into three fractions based on the hydrophobicity [i.e., hydrophobic (HPO), transphilic (TPH) and hydrophilic (HPI)]. DOM mass balances and DBP reactivity checks were performed to characterize the effects of isolation and fractionation steps. The fractions were chloraminated at three pHs and three bromide concentrations. The results showed that pH was the most important factor controlling HAA formation and speciation. The HAA yields significantly decreased with increase in pH from 6.3 to 9.0. The impact of bromide in the formation of brominated HAA species also became less important with increasing pH, and no brominated specie was detectable at pH 9. HPO fractions of the two source waters consistently showed higher HAA yields than TPH and HPI fractions. On the other hand, HPI fractions showed higher bromine incorporation than HPO and TPH fractions. To maintain higher and relatively stable combined chlorine residuals while reducing HAA formation, water utilities may consider keeping pH above 7.5 as one strategy. This will also lower the formation of brominated HAA species which have been shown to be more cyto- and geno-toxic than their chlorinated analogs. PMID:23245540

Hong, Ying; Song, Hocheol; Karanfil, Tanju

2013-03-01

32

Method of analysis at the U.S. Geological Survey California Water Science Center, Sacramento Laboratory - determination of haloacetic acid formation potential, method validation, and quality-control practices  

USGS Publications Warehouse

An analytical method for the determination of haloacetic acid formation potential of water samples has been developed by the U.S. Geological Survey California Water Science Center Sacramento Laboratory. The haloacetic acid formation potential is measured by dosing water samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine. The haloacetic acids formed are bromochloroacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, tribromoacetic acid, and trichloroacetic acid. They are extracted, methylated, and then analyzed using a gas chromatograph equipped with an electron capture detector. Method validation experiments were performed to determine the method accuracy, precision, and detection limit for each of the compounds. Method detection limits for these nine haloacetic acids ranged from 0.11 to 0.45 microgram per liter. Quality-control practices include the use of blanks, quality-control samples, calibration verification standards, surrogate recovery, internal standard, matrix spikes, and duplicates.

Zazzi, Barbara C.; Crepeau, Kathryn L.; Fram, Miranda S.; Bergamaschi, Brian A.

2005-01-01

33

Effects Of Haloacetic Acids and their major metabolites in a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) Assay  

EPA Science Inventory

The haloacetic acids (HAAs) are a class of chemicals produced by disinfection of drinking water. Many of the HAAs are developmental toxicants when administered to rodents producing a variety of developmental effects. We have previously shown that the HAAs can produce direct effec...

34

Direct Determination of Trace-Level Haloacetic Acids in Drinking Water by Two-1 Dimensional Ion Chromatography with Suppressed Conductivity2  

E-print Network

of disinfection by-products36 During thedisinfection step of drinking water treatment process, disinfectants disinfection38 by-products(DBPs). Among the six hundred substances identified, haloacetic acids (HAAs) and39 thetreatment process of drinking water, disinfectants (chlorine, ozone, chlorine dioxide)13 react on water

Boyer, Edmond

35

Trace determination of nine haloacetic acids in drinking water by liquid chromatography-electrospray tandem mass spectrometry.  

PubMed

A simple, fast and sensitive liquid chromatography-electrospray tandem mass spectrometry method was established for trace levels of nine haloacetic acids (HAAs) in drinking water. Water samples were removed of residual chlorine by adding L-ascorbic acid, and directly injected after filtered by 0.22 microm membrane. Nine HAAs were separated by liquid chromatography in 7.5 min, and the limits of detection were generally between 0.16 and 0.99 microg/L except for chlorodibromoacetic acid (1.44 microg/L) and tribromoacetic acid (8.87 microg/L). The mean recoveries of nine target compounds in spiked drinking water samples were 80.1-108%, and no apparent signal suppression was observed. Finally, this method was applied to determine HAAs in the tap water samples collected from five waterworks in Shandong, China. Nine HAAs except for monochloroacetic acid, monobromoacetic acid, dibromochloroacetic acid and tribromoacetic acid were detected, and the total concentrations were 7.79-36.5 microg/L. The determination results well met the first stage of the Disinfectants/Disinfection By-Products (D/DBP) Rules established by U.S.EPA and Guidelines for Drinking-water Quality of WHO. PMID:20538280

Meng, Liping; Wu, Shimin; Ma, Fujun; Jia, Ai; Hu, Jianying

2010-07-16

36

The fate of haloacetic acids and trihalomethanes in an aquifer storage and recovery program, Las Vegas, Nevada  

USGS Publications Warehouse

The fate of disinfection byproducts during aquifer storage and recovery (ASR) is evaluated for aquifers in Southern Nevada. Rapid declines of haloacetic acid (HAA) concentrations during ASR, with associated little change in Cl concentration, indicate that HAAs decline primarily by in situ microbial oxidation. Dilution is only a minor contributor to HAA concentration declines during ASR. Trihalomethane (THM) concentrations generally increased during storage of artificial recharge (AR) water and then declined during recovery. The decline of THM concentrations during recovery was primarily from dilution of current season AR water with residual AR water remaining in the aquifer from previous ASR seasons and native ground water. In more recent ASR seasons, for wells with the longest history of ASR, brominated THMs declined during storage and recovery by processes in addition to dilution. These conclusions about THMs are indicated by THM/Cl values and supported by a comparison of measured and model predicted THM concentrations. Geochemical mixing models were constructed using major-ion chemistry of the three end-member waters to calculate predicted THM concentrations. The decline in brominated THM concentrations in addition to that from dilution may result from biotransformation processes.

Thomas, J.M.; McKay, W.A.; Colec, E.; Landmeyer, J.E.; Bradley, P.M.

2000-01-01

37

GAS CHROMATOGRAPHY/MASS SPECTROMETRY STUDY OF MIXED HALOACETIC ACIDS FOUND IN CHLORINATED DRINKING WATER  

EPA Science Inventory

Over the last two years, our laboratory and others have identified mono-, di-, and trichloro- acetic acids as major byproducts of drinking water disinfection. n areas of the country where relatively high levels of bromine ion are naturally present in the source water, it is expec...

38

Andy Haas -5/21/2010 Slide 1 LHC DATA!LHC DATA!  

E-print Network

West Coast LHC Theory MeetingWest Coast LHC Theory Meeting SCIPP, UC Santa CruzSCIPP, UC Santa Cruz May/21/2010 Slide 6 #12;Andy Haas - 5/21/2010 Slide 7 Collision xs ~ 80 mb Collision rate ~ 100 Hz Record every collision to tape! #12;Andy Haas - 5/21/2010 Slide 8 #12;Andy Haas - 5/21/2010 Slide 9 Squeeze #12;Andy Haas

California at Santa Cruz, University of

39

Determination of ten haloacetic acids in drinking water using high-performance and ultra-performance liquid chromatography-tandem mass spectrometry.  

PubMed

Haloacetic acids (HAAs) are a class of byproducts resulting from the reaction of chlorinated disinfectants with natural organic matter. These chemicals have been found in animal studies to possibly influence hepatic, reproductive, and developmental functions, and they may be mutagenic and carcinogenic. Because HAAs are hydrophilic and strongly acidic, it is a challenge to measure them at low levels. In this study, nine traditional HAAs and monoiodoacetic acid, an emerging disinfection byproduct, are analyzed in water directly. HAAs were separated on a BetaMax Acid column or a HILIC UPLC column, and they were detected by negative electrospray ionization-tandem mass spectrometry. Although the on-column limits of detection of HAAs were lower when using an HILIC UPLC column (0.08-2.73 microg/L) than when using a BetaMax Acid column (0.18 to 71.5 microg/L), to use an HILIC UPLC column, it was required to dissolve water samples in 90% acetonitrile before injection and result in sample dilution. BetaMax Acid column was found to be more suitable for the analysis of HAAs in drinking water because there was no need of sample preparation. Major species of HAAs, such as dichloroacetic acid and trichloroacetic acid, and other primary species (e.g., dibromoacetic acid, bromochloroacetic acid and bromodichloroacetic acid) can be detected using the BetaMax Acid column at concentrations higher than 1-3 microg/L. PMID:19161659

Chen, Chia-Yang; Chang, Shueh-Ni; Wang, Gen-Shuh

2009-01-01

40

An Optimized Analytical Method for the Simultaneous Detection of Iodoform, Iodoacetic Acid, and Other Trihalomethanes and Haloacetic Acids in Drinking Water  

PubMed Central

An optimized method is presented using liquid-liquid extraction and derivatization for the extraction of iodoacetic acid (IAA) and other haloacetic acids (HAA9) and direct extraction of iodoform (IF) and other trihalomethanes (THM4) from drinking water, followed by detection by gas chromatography with electron capture detection (GC-ECD). A Doehlert experimental design was performed to determine the optimum conditions for the five most significant factors in the derivatization step: namely, the volume and concentration of acidic methanol (optimized values ?=?15%, 1 mL), the volume and concentration of Na2SO4 solution (129 g/L, 8.5 mL), and the volume of saturated NaHCO3 solution (1 mL). Also, derivatization time and temperature were optimized by a two-variable Doehlert design, resulting in the following optimized parameters: an extraction time of 11 minutes for IF and THM4 and 14 minutes for IAA and HAA9; mass of anhydrous Na2SO4 of 4 g for IF and THM4 and 16 g for IAA and HAA9; derivatization time of 160 min and temperature at 40°C. Under optimal conditions, the optimized procedure achieves excellent linearity (R2 ranges 0.9990–0.9998), low detection limits (0.0008–0.2 µg/L), low quantification limits (0.008–0.4 µg/L), and good recovery (86.6%–106.3%). Intra- and inter-day precision were less than 8.9% and 8.8%, respectively. The method was validated by applying it to the analysis of raw, flocculated, settled, and finished waters collected from a water treatment plant in China. PMID:23613747

Jiang, Songhui; Templeton, Michael R.; He, Gengsheng; Qu, Weidong

2013-01-01

41

Direct injection ion chromatography for the control of chlorinated drinking water: simultaneous estimation of nine haloacetic acids and quantitation of bromate, chlorite and chlorate along with the major inorganic anions.  

PubMed

Most methods for the analysis of haloacetic acids published in recent years are based on ion chromatography with direct injection, employing a gradient elution with potassium hydroxide (KOH). This work reports the exploration of an alternative eluent, a buffer of sodium carbonate/sodium hydrogen carbonate, aimed at the simultaneous analysis of nine haloacetic acids along with bromate, chlorite and chlorate. The alternative of both a less alkaline eluent and a lower temperature of operation may prevent the partial decomposition of some of the haloacetic acids during the analytical process, especially the more vulnerable brominated ones. Gradient elution at temperature of 7 °C yielded the best results, with an acceptable separation of 17 analytes (which includes the major natural inorganic anions) and a good linearity. Precision ranges from 0.3 to 23.4 (% V.C.), and detection limits are within units of ?g L?¹, except for tribromoacetic acid - somewhat high in comparison with those of the official methods. Nonetheless, with the basic instrumentation setup herein described, this method may be suitable for monitoring when the drinking water treatments are to be optimized. This is especially interesting for small communities or for developing/developed countries in which regulations on disinfection by-products others than trihalomethanes are being addressed. PMID:25252348

Garcia-Villanova, Rafael J; Raposo Funcia, César; Oliveira Dantas Leite, M Vilani; Toruño Fonseca, Ivania M; Espinosa Nieto, Miguel; Espuelas India, Javier

2014-09-01

42

Determination of Haloacetic Acids in Bottled and Tap Water Sources by Dispersive Liquid-Liquid Microextraction and GC-MS Analysis  

PubMed Central

Haloacetic acids are toxic organic pollutants that can be formed as by-products of disinfection of water by chlorination. In this study, we developed a fast and efficient method for the determination of six species of these compounds in water using dispersive liquid-liquid microextraction followed by GC-MS analysis. To be suitable for GC analysis, the acidic analytes were derivatized using n-octanol. One-factor-at-a-time optimization was carried out on several factors including temperature, extraction time, amount of catalyst, and dispersive solvent. The optimized conditions were then used to determine calibration parameters. Linearity, as demonstrated by coefficient of determination, ranged between 0.9900 and 0.9966 for the concentration range of 0.05–0.57?µg/L. The proposed method has good repeatability; intraday precision was calculated as %RSD of 2.38–9.34%, while interday precision was 4.69–8.06%. The method was applied to real samples in bottled water and tap water sources. Results indicated that the total concentrations of the analytes in these sources (2.97–5.30?µg/L) were far below the maximum contaminant levels set by both the World Health Organization and the United States Environmental Protection Agency. The proposed method compared favorably with methods reported in the literature. PMID:25295305

Al-shatri, Mohsen A.; Nuhu, Abdulmumin A.; Basheer, Chanbasha

2014-01-01

43

Determination of haloacetic acids in bottled and tap water sources by dispersive liquid-liquid microextraction and GC-MS analysis.  

PubMed

Haloacetic acids are toxic organic pollutants that can be formed as by-products of disinfection of water by chlorination. In this study, we developed a fast and efficient method for the determination of six species of these compounds in water using dispersive liquid-liquid microextraction followed by GC-MS analysis. To be suitable for GC analysis, the acidic analytes were derivatized using n-octanol. One-factor-at-a-time optimization was carried out on several factors including temperature, extraction time, amount of catalyst, and dispersive solvent. The optimized conditions were then used to determine calibration parameters. Linearity, as demonstrated by coefficient of determination, ranged between 0.9900 and 0.9966 for the concentration range of 0.05-0.57 µg/L. The proposed method has good repeatability; intraday precision was calculated as %RSD of 2.38-9.34%, while interday precision was 4.69-8.06%. The method was applied to real samples in bottled water and tap water sources. Results indicated that the total concentrations of the analytes in these sources (2.97-5.30 µg/L) were far below the maximum contaminant levels set by both the World Health Organization and the United States Environmental Protection Agency. The proposed method compared favorably with methods reported in the literature. PMID:25295305

Al-shatri, Mohsen A; Nuhu, Abdulmumin A; Basheer, Chanbasha

2014-01-01

44

Ultrasonic enhancement of leaching and in situ derivatization of haloacetic acids in vegetable foods prior to gas chromatography-electron capture detection.  

PubMed

A continuous ultrasound-assisted approach to enhance the extraction of nine haloacetic acids (HAAs) from vegetables with in situ derivatization to methyl esters for their gas chromatography (GC) analysis is presented. The optimization of simultaneous extraction (using acidic methanol as extractant) and derivatization enabled the completion of both steps in 15 min. Ultrasound assistance has proved to enhance both linked steps, which results in a considerable shortening of the overall analysis time (i.e. 552.1 and 552.2 EPA methods for analysis of these compounds in drinking water require 1 and 2 h, respectively, only for derivatization). After sample preparation, the esterified HAAs were isolated by liquid-liquid extraction with n-hexane and analysed by GC-electron capture detection. The proposed method is an interesting alternative to present methods for the determination of HAAs in vegetable foods. This is an area unjustifiably forgotten by reference laboratory organisms as proved by the absence of official methods for analysis of the target compounds in these samples. The proposed method can be applied to the analysis of HAAs in any solid sample after optimization of the main variables involved in the extraction-derivatization step. PMID:18586256

Alvarez Sánchez, B; Priego Capote, F; Luque de Castro, M D

2008-08-01

45

Pyruvate Remediation of Cell Stress and Genotoxicity Induced by Haloacetic Acid Drinking Water Disinfection By-Products  

PubMed Central

Monohaloacetic acids (monoHAAs) are a major class of drinking water disinfection by-products (DBPs) and are cytotoxic, genotoxic, mutagenic, and teratogenic. We propose a model of toxic action based on monoHAA-mediated inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a target cytosolic enzyme. This model predicts that GAPDH inhibition by the monoHAAs will lead to a severe reduction of cellular ATP levels and repress the generation of pyruvate. A loss of pyruvate will lead to mitochondrial stress and genomic DNA damage. We found a concentration-dependent reduction of ATP in Chinese hamster ovary cells after monoHAA treatment. ATP reduction per pmol monoHAA followed the pattern of iodoacetic acid (IAA) > bromoacetic acid (BAA) >> chloroacetic acid (CAA), which is the pattern of potency observed with many toxicological endpoints. Exogenous supplementation with pyruvate enhanced ATP levels and attenuated monoHAA-induced genomic DNA damage as measured with single cell gel electrophoresis. These data were highly correlated with the SN2 alkylating potentials of the monoHAAs and with the induction of toxicity. The results from this study strongly support the hypothesis that GAPDH inhibition and the possible subsequent generation of reactive oxygen species is linked with the cytotoxicity, genotoxicity, teratogenicity, and neurotoxicity of these DBPs. PMID:23893730

Dad, Azra; Jeong, Clara H.; Pals, Justin A.; Wagner, Elizabeth D.; Plewa, Michael J.

2014-01-01

46

Influence of soluble microbial products (SMP) on wastewater disinfection byproducts: trihalomethanes and haloacetic acid species from the chlorination of SMP  

Microsoft Academic Search

Introduction  Effluent organic matter from biological wastewater treatment plants is composed of degradation products and soluble microbial\\u000a products (SMP). Protein, polysaccharide, humic acid, and DNA were major biomolecules of SMP. Little is known about the effects\\u000a of SMP as microbially derived precursors on disinfection byproduct formation and speciation in biologically treated wastewater.\\u000a In addition, there has never been any attempt to

Yuan-yuan Wei; Yan Liu; Yun Zhang; Rui-hua Dai; Xiang Liu; Jin-jian Wu; Qiang Zhang

2011-01-01

47

CAN ABIOTIC (INORGANIC) PROCESSES ACCOUNT FOR HALOACETATE CONCENTRATION PROFILES?  

EPA Science Inventory

Haloacetates comprise about 13% of the measurable halogenated organic matter in potable water supplies after chlorination. Some of these species have been linked with animal carcinogenesis and are regulated under the Stage 1 DBP Rule. However, it is known that post-disinfection p...

48

ACUTE SPERMATOGENIC EFFECTS OF BROMOACETIC ACIDS  

EPA Science Inventory

Chlorine and bromine, when present, can react with natural organic substances in source waters to form haloacetic acids, major by-products of chlorine disinfection. everal toxic effects including testicular damage have been attributed to chloroacetic acids but little information ...

49

Developmental toxicity of mixtures: the water disinfection by-products dichloro-, dibromo- and bromochloro acetic acid in rat embryo culture  

EPA Science Inventory

The chlorination of drinking water results in production of numerous disinfection by-products (DBPs). One of the important classes of DBPs is the haloacetic acids. We have previously shown that the haloacetic acids (HAs), dichloro (DCA), dibromo (DBA) and bromochloro (BCA) acetic...

50

MIXING RATIO INFLUENCES HALOACETIC ACID (HAA) MIXTURE TOXICITY  

EPA Science Inventory

Mixtures of the same type (for example, disinfection byproduct mixtures) often contain the same chemicals, but at varying concentrations. The objective of the present study was to examine the influence of mixing ratio (the concentrations of chemicals relative to one another) on ...

51

FORMATION AND ENANTIOSELECTIVE BIODEGRADATION OF THE ENANTIOMERS OF BROMOCHLOROACETIC ACID  

EPA Science Inventory

Bromochloroacetic acid (BCAA) is formed by chlorination of drinking waters containing naturally occurring bromide. This haloacetic acid is a concern to public health because of suspected carcinogenicity and toxicity, and is a potential target of disinfectant byproduct regulations...

52

DRINKING WATER DISINFECTION BYPRODUCTS AND DURATION OF GESTATION  

EPA Science Inventory

Recent studies of drinking water disinfection by-products (DBPs) suggest high exposure decreases risk of preterm birth. We examined this association with total trihalomethane (TTHM) and five haloacetic acids (HAA5) among 2,041 women in a prospective pregnancy study conducted from...

53

THE FATE OF THE HALOACETATES IN DRINKING WATER - CHEMICAL KINETICS IN AQUEOUS SOLUTION  

EPA Science Inventory

Haloacetates comprise about 13% of the measurable halogenated organic matter in potable water supplies after chlorination. Some of these species have been linked with animal carcinogenesis and are regulated under the Stage 1 Disinfection Byproduct (DBP) Rule. However, it is known...

54

AVOIDING PITFALLS IN THE DETERMINATION OF HALOCARBOXYLIC ACIDS: THE PHOTOCHEMISTRY OF METHYLATION  

EPA Science Inventory

Haloethanoic (haloacetic) acids are formed during chlorination of drinking water and are regulated by the Environmental Protection Agency (EPA). These compounds are normally quantified by gas chromatography with electron capture detection (GC-ECD) ad the methyl esters. EPA Meth...

55

Structure of haloacetate-catabolic IncP-1beta plasmid pUO1 and genetic mobility of its residing haloacetate-catabolic transposon.  

PubMed

The self-transmissible plasmid pUO1 from Delftia acidovorans strain B carries two haloacetate-catabolic transposons, TnHad1 and TnHad2, and the mer genes for resistance to mercury. The complete 67,066-bp sequence of pUO1 revealed that the mer genes were also carried by two Tn402/Tn5053-like transposons, Tn4671 and Tn4672, and that the pUO1 backbone regions shared 99% identity to those of the archetype IncP-1beta plasmid R751. Comparison of pUO1 with three other IncP-1beta plasmids illustrated the importance of transposon insertion in the diversity and evolution of this group of plasmids. Mutational analysis of the four outermost residues in the inverted repeats (IRs) of TnHad2, a Tn21-related transposon, revealed a crucial role of the second residue of its IRs in transposition. PMID:14594853

Sota, Masahiro; Kawasaki, Haruhiko; Tsuda, Masataka

2003-11-01

56

The relationship between disinfection by-products formation and characteristics of natural organic matter in raw water  

Microsoft Academic Search

The influence of the characteristics of natural organic matter (NOM) on disinfection by-product formation was investigated\\u000a for Maeri raw water, located in downstream of Nakdong river and Hoedong reservoir at Busan in Korea. The NOM was chlorinated\\u000a and analyzed for trihalomethanes (THMs), 5 haloacetic acids (HAA-5) and total organic halide (TOX). Aromatic contents determined\\u000a by specific UV absorbance at 254

Chul-Woo Jung; Hee-Jong Son

2008-01-01

57

MASS SPECTROMETRY FOR RISK MANAGEMENT OF DRINKING WATER TREATMENT; II. DISINFECTION BY-PRODUCTS: HALOACETIC ACIDS  

EPA Science Inventory

Risk management of drinking water relies on quality analytical data. Analytical methodology can often be adapted from environmental monitoring sources. However, risk management sometimes presents special analytical challenges because data may be needed from a source for which n...

58

HALOACETONITRILES VS. REGULATED HALOACETIC ACIDS: ARE NITROGEN CONTAINING DBPS MORE TOXIC?  

EPA Science Inventory

Haloacetonitriles (HANs) are toxic nitrogenous drinking water disinfection by-products (N-DBPs) and are observed with chlorine, chloramine, or chlorine dioxide disinfection. Using microplate-based Chinese hamster ovary (CHO) cell assays for chronic cytotoxicity and acute genotoxi...

59

Using the mouse embryonic stem cell test (EST) to evaluate the embryotoxicity of haloacetic acids  

EPA Science Inventory

The Embryonic Stem Cell Test (EST) is used to predict the embryotoxic potential of a test compound by combining the data from cytotoxicity assays in undifferentiated mouse embryonic stem (mES) cells and differentiated mouse cells with the data from a differentiation assay in mES ...

60

DIBROMOACETIC ACID-INDUCED ELEVATIONS OF ESTRADIOL IN THE CYCLING AND OVARIECTOMOZED/ESTRADIOL-IMPLANTED FEMALE RAT  

EPA Science Inventory

Goldman, JM and Murr, AS. Dibromoacetic Acid-induced Elevations of Estradiol in Both Cycling and Ovariectomized / Estradiol-implanted Female Rats ABSTRACT Haloacetic acids are one of the principal classes of disinfection by-products generated by the chlorination of mun...

61

ALTERED CRANIOFACIAL GENE EXPRESSION OF NEURULATION STAGED MOUSE EMBRYO CULTURES EXPOSED TO BROMOCHLOROACETIC ACID  

EPA Science Inventory

An unintended consequence of chemical disinfection of municipal drinking water is the production of chemical disinfection by-products (DBPs). A major class ofDBPs are haloacetic acidsthat may be found at concentrations higher than other DBPs. Bromochloroacetic acid (BCA) is a de...

62

The Effect of Water Disinfection By-products on Pregnancy Outcomes in Two Southeastern U.S. Communities  

PubMed Central

Objective To determine if exposure to DBPs during gestation increases the risk of adverse birth outcomes, specifically term small for gestational age (SGA) birth, preterm birth (PTB), and very PTB (<32 weeks gestation). Methods We used weekly measurements total trihalomethanes (TTHMs), 5 haloacetic acids (HAA5), and total organic halides (TOX) collected from two distribution systems to evaluate the associations between DBP concentrations and term SGA, PTB and very PTB using logistic regression. Results We found no associations between DBPs and term-SGA. In the site with higher concentrations of bromine-containing DBPs, we found an association between TOX and PTB; this association was larger, though less precise, for very PTB. Conclusions Our results do not support an association between TTHMs or HAA5 and the birth outcomes investigated, but an association was found between increased TOX and PTB. PMID:21915074

Horton, Bethany Jablonski; Luben, Thomas J.; Herring, Amy H.; Savitz, David A.; Singer, Philip C.; Weinberg, Howard S.; Hartmann, Katherine E.

2013-01-01

63

The impact of bromide on the formation of neutral and acidic disinfection by-products (DBPs) in Mediterranean chlorinated drinking water  

Microsoft Academic Search

By using the Grob closed loop stripping analysis technique a wide variety of disinfection by-products (DBPs) was determined, in finished drinking water of 15 important cities of Greece distributed in the southern, northern, west continental land and in the islands of Aegean and Ionian Seas. Trihalomethanes, haloacetonitriles, haloacetic acids, chloropicrin, halogenated ketons and chloral hydrate were the main DBPs determined.

Adamantia A. Kampioti; Euripides G. Stephanou

2002-01-01

64

ALTERATION OF ESTROUS CYCLICITY BY THE DRINKING WATER DISINFECTION BY-PRODUCT DIBROMOACETIC ACID: RELATIONSHIP TO AN EFFECT ON ESTRADIOL METABOLISM?  

EPA Science Inventory

A number of chemicals formed by disinfection of municipal drinking water have been suspected to cause reproductive alterations in humans and test animals. One class of these chemicals, the haloacetic acids, have been reported to alter a number of rat testicular endpoints, includ...

65

EFFECTS OF DEFINED MIXTURES OF TRIHALOMETHANES AND HALOACETIC ACIDS ON PREGNANCY MAINTENANCE AND EYE DEVELOPMENT IN F 344 RATS  

EPA Science Inventory

Although disinfection of drinking water is important for control of microbial contamination, it results in the formation of hundreds of disinfection by-products (DBPs). The most prevalent DBPs are trihalomethanes (THMs; chloroform, bromodichloromethane, chlorodibromomethane, bro...

66

EVALUATION OF THE JOINT TOXIC ACTION OF MIXTURES OF HALOACETIC ACIDS CONSTRUCTED USING ENVIRONMENTAL CONCENTRATION/EXPOSURE DATA  

EPA Science Inventory

Disinfection byproducts (DBPs) are formed by reactions between chemicals used to disinfect water and organic compounds present in source water. The composition of DBP mixtures varies based on a number of factors, including treatment scenario, with different DBP mixtures contain...

67

Enthalpies of crystal lattices and standard enthalpies of formation of crystalline metal haloacetates  

NASA Astrophysics Data System (ADS)

A method for the calculation of the enthalpies of crystal lattices and standard enthalpies of formation of anhydrous metal nitrates is presented. The estimation of ÄHlat is based on interpolation of the linear plots of this value vs. the Edwards parameter, which, in turn, is a linear function of the logarithm of the acid dissociation constant. Linearity of the above dependence was previously found experimentally for the corresponding uranyl salts. Previously unknown lattice enthalpies and standard enthalpies of formation of a large set of anhydrous metal nitrates and carboxylates are calculated.

Baluev, A. V.

1999-01-01

68

Disinfection byproduct formation resulting from settled, filtered, and finished water treated by titanium dioxide photocatalysis.  

PubMed

This study evaluated strategies targeting disinfection byproduct (DBP) mitigation using TiO2 photocatalysis with varying influent water quality. A Purifics Photo-CAT Lab reactor was used to assess total trihalomethane (TTHM) and haloacetic acid (HAA) formation as a function of photocatalytic treatment using water from a conventional coagulation/flocculation/sedimentation process, granular activated carbon filtration, and a DBP hot spot in the water distribution system. Regardless of influent water quality, photocatalysis reduced DBP precursors; however, low-energy limited photocatalysis (<5 kW h m(-3)), exacerbated the production of TTHMs and HAA5s beyond initial levels. Accordingly, limited photocatalysis is not a suitable option when TTHMs and HAA5s are a concern, regardless of the level of pretreatment. Limited photocatalysis yields incomplete oxidation, wherein larger, more aromatic, humic organic compounds are broken into smaller molecular weight, less aromatic, and less humic moieties, which have considerable potential to produce DBPs. More complete mineralization of DBP precursors is obtained using extended photocatalysis (80-160 kW h m(-3)), which substantially decreases DBP precursors as well as TTHM and HAA5 concentrations. In order to balance DBP mitigation, energy, and chemical usage, targeted use of TiO2 photocatalysis is necessary in a water treatment train (e.g., extended photocatalysis at a distribution system hot spot, where the volumetrically high energy requirements may be justifiable). PMID:24972073

Mayer, Brooke K; Daugherty, Erin; Abbaszadegan, Morteza

2014-12-01

69

Simultaneous determination of halogenated neutral and acidic disinfection by-products in drinking water by closed-loop stripping extraction and capillary gas chromatography  

Microsoft Academic Search

The analytical capabilities of Grob closed-loop stripping analysis technique were evaluated for the determination, in drinking water, of trihalomethanes, haloacetonitriles, haloacetic acids, chloropicrin, halogenated ketones and chloral hydrate, reported as chlorination disinfection by-products. Thus by one-step enrichment and isolation procedure and subsequent analysis by capillary gas chromatography with electron-capture detection, organic polar and non-polar disinfection by-products could be analyzed at

Adamantia A. Kampioti; Euripides G. Stephanou

1999-01-01

70

Formation and modeling of disinfection by-products in drinking water of six cities in China.  

PubMed

Water quality parameters including TOC, UV(254), pH, chlorine dosage, bromide concentration and disinfection by-products were measured in water samples from 41 water treatment plants of six selected cities in China. Chloroform, bromodichloromethane, dibromochloromethane, dichloroacetic acid and trichloroacetic acid were the major disinfection by-products in the drinking water of China. Bromoform and dibromoacetic acid were also detected in many water samples. Higher concentrations of trihalomethanes and haloacetic acids were measured in summer compared to winter. The geographical variations in DBPs showed that TTHM levels were higher in Zhengzhou and Tianjin than other selected cities. And the HAA5 levels were highest in Changsha and Tianjin. The modeling procedure that predicts disinfection by-products formation was studied and developed using artificial neural networks. The performance of the artificial neural networks model was excellent (r > 0.84). PMID:21416099

Ye, Bixiong; Wang, Wuyi; Yang, Linsheng; Wei, Jianrong; E, Xueli

2011-05-01

71

Occurrence of disinfection by-products in tap water distribution systems and their associated health risk.  

PubMed

The concentrations of trihalomethanes (THMs), including chloroform, bromodichloromethane, dibromochloromethane, and bromoform, and haloacetic acids (HAAs; monochloroacetic acid, monobromoacetic acid, dibromoacetic acid, dichloroacetic acid, and trichloroacetic acid) were measured in tap waters passing through water distribution systems of six water treatment plants in Seoul, Korea, and their associated health risks from exposure to THMs through ingestion, dermal contact, and inhalation were estimated using a probabilistic approach. The concentration ranges for total THMs and HAA5 were 3.9-53.5 and acid, and trichloroacetic acid were the most frequently detected. Spatial and seasonal variations in concentrations of THMs and HAAs in the six water distribution systems were significant (P < 0.001).The mean lifetime cancer risks through ingestion, dermal contact, and inhalation during showering ranged as 7.23-10.06 × 10(-6), 2.19-3.63 × 10(-6), and 5.22-7.35 × 10(-5), respectively. The major exposure route to THMs was inhalation during showering. Sensitivity analysis showed that shower time and shower frequency had a great impact on the lifetime cancer risk by the exposure to THMs in tap water. PMID:23446885

Lee, Jin; Kim, Eun-Sook; Roh, Bang-Sik; Eom, Seog-Won; Zoh, Kyung-Duk

2013-09-01

72

Chlorodifluoroacetic acid fate and toxicity to the macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum in aquatic microcosms.  

PubMed

Chlorodifluoroacetic acid (CDFA) is a novel haloacetic acid (HAA) and has been recently documented in aquatic systems. It is a suspected degradation product of the refrigerants 1,1,2-trichloro-1,1-difluoroethane (CFC-113) and 1-chloro-1,1-difluoroethane (HCFC-142b). Haloacetic acids can be phytotoxic, putatively acting through inhibition of the citric acid cycle. Replicate (n = 3) 12,000-L model aquatic ecosystems (microcosms) were dosed once at 0.5, 1, 5, and 20 mg/L of neutralized CDFA. Three microcosms served as controls. Each microcosm was stocked with eight individual apical shoots of both Myriophyllum spicatum and Myriophyllum sibiricum and sampled at regular intervals over a 42-d exposure period. The plants were assessed for the somatic endpoints of plant length, root growth, node number, and wet and dry mass and the biochemical endpoints of chlorophyll-a/b and carotenoid content as well as citric acid levels. The duckweed Lemna gibba was also introduced into these systems and monitored over a period of 14 d for wet/dry mass, plant/frond number, chlorophyll content, and growth rate. Concentrations of CDFA remained constant in the water column over the course of the fate investigation (241 d), indicating that this compound undergoes little, if any, degradation in aquatic systems. Results showed few statistically significant differences from controls for all three plant species with exposure to CDFA but no biologically relevant impacts. Overall, CDFA does not appear to pose any risk to these aquatic macrophytes at current environmental concentrations. PMID:11764159

Hanson, M L; Sibley, P K; Mabury, S A; Muir, D C; Solomon, K R

2001-12-01

73

Tribromopyrrole, brominated acids, and other disinfection byproducts produced by disinfection of drinking water rich in bromide.  

PubMed

Using gas chromatography/mass spectrometry (GC/MS), we investigated the formation of disinfection byproducts (DBPs) from high bromide waters (2 mg/L) treated with chlorine or chlorine dioxide used in combination with chlorine and chloramines. This study represents the first comprehensive investigation of DBPs formed by chlorine dioxide under high bromide conditions. Drinking water from full-scale treatment plants in Israel was studied, along with source water (Sea of Galilee) treated under carefully controlled laboratory conditions. Select DBPs (trihalomethanes, haloacetic acids, aldehydes, chlorite, chlorate, and bromate) were quantified. Many of the DBPs identified have not been previously reported, and several of the identifications were confirmed through the analysis of authentic standards. Elevated bromide levels in the source water caused a significant shift in speciation to bromine-containing DBPs; bromoform and dibromoacetic acid were the dominant DBPs observed, with very few chlorine-containing compounds found. Iodo-trihalomethanes were also identified, as well as a number of new brominated carboxylic acids and 2,3,5-tribromopyrrole, which represents the first time a halogenated pyrrole has been reported as a DBP. Most of the bromine-containing DBPs were formed during pre-chlorination at the initial reservoir, and were not formed by chlorine dioxide itself. An exception wasthe iodo-THMs, which appeared to be formed by a combination of chlorine dioxide with chloramines or chlorine (either added deliberately or as an impurity in the chlorine dioxide). A separate laboratory study was also conducted to quantitatively determine the contribution of fulvic acids and humic acids (from isolated natural organic matter in the Sea of Galilee) as precursor material to several of the DBPs identified. Results showed that fulvic acid plays a greater role in the formation of THMs, haloacetic acids, and aldehydes, but 2,3,5-tribromopyrrole was produced primarily from humic acid. Because this was the first time a halopyrrole has been identified as a DBP, 2,3,5-tribromopyrrole was tested for mammalian cell cytotoxicity and genotoxicity. In comparison to other DBPs, 2,3,5-tribromopyrrole was 8x, 4.5x, and 16x more cytotoxic than dibromoacetic acid, 3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone [MX], and potassium bromate, respectively. 2,3,5-Tribromopyrrole also induced acute genomic damage, with a genotoxic potency (299 microM) similar to that of MX. PMID:12967096

Richardson, Susan D; Thruston, Alfred D; Rav-Acha, Chaim; Groisman, Ludmila; Popilevsky, Inna; Juraev, Olga; Glezer, Victor; McKague, A Bruce; Plewa, Michael J; Wagner, Elizabeth D

2003-09-01

74

Synthesis of hydroxyeicosatetraenoic acids (HETE's) by adrenal glomerulosa cells and incorporation into cellular lipids  

SciTech Connect

The role of lipoxygenase metabolites of arachidonic acid (AA) in the regulation of aldosterone secretion was studied in isolated rat adrenal glomerulosa cells. Cells were incubated with /sup 14/C-AA in the presence of angiotensin (AII). The media was extracted, metabolites isolated by HPLC, and structures of the metabolites determined by UV absorbance and mass spectrometry. The major products were 12- and 15-HETE with lesser amounts of 11- and 5-HETE. When adrenal cells were incubated with 15-, 12- or 5-HPETE or their respective HETE's (0.03-300nM), there was no significant change in basal or AII-stimulated aldosterone release. Cells were incubated with (/sup 3/H)-AA, -5-HETE, -15-HETE, -12-HETE or -LTB. The cellular lipids were extracted and analyzed by TLC. AA was incorporated into phospholipids (22%), cholesterol esters (50%) and triglycerides (21%). Neither the HETE's or LTB/sub 4/ were incorporated into phospholipids. 5-HETE was taken up into di- and mono-glycerides. The rates of incorporation of AA and 5-HETE were similar (+ 1/2 = 10 min). The incorporation of 5-HETE into glycerol esters did not modify the release of aldosterone by the cells. Thus, while adrenal cells synthesize HETE's, these eicosanoids do not appear to alter the synthesis of aldosterone.

Campbell, W.B.; Richards, C.F.; Brady, M.T.; Falck, J.R.

1986-03-05

75

Monochloramine loss in the presence of humic acid.  

PubMed

Free chlorine has been used extensively as a primary and secondary disinfectant for potable water. Where it is difficult to maintain a free chlorine residual or when disinfection by-products (DBPs) are of concern, monochloramine has been used to provide a stable disinfectant residual in distributions systems. Reactions of disinfectants, free chlorine or monochloramine, with natural organic matter (NOM) consequently result in the formation of DBPs such as trihalomethanes and haloacetic acids. However, few studies have focused on the fate and kinetics of monochloramine loss in the presence of reactive constituents such as NOM. Monochloramine is inherently unstable and decays even without reactive constituents present via a mechanism known as autodecomposition. Therefore, to predict monochloramine concentrations in the presence of NOM is clearly associated with the ability to adequately model autodecomposition. This study presents the results of a semi-mechanisiic model capable of predicting the loss of monochloramine in the presence of humic material in the pH range of 6.55-8.33. The model accounts for both fast and a slow monochloramine demand to explain the loss of monochloramine over the pH range of this study. The formation of dichloroacetic acid was also predicted due to the ability of the model to differentiate monochloramine reaction pathways in the presence NOM. The results shown here demonstrate the ability of a semi-mechanistic model to predict monochloramine residuals and DBP formation in the presence of humic material. PMID:11871712

Duirk, Stephen E; Gombert, Bertrand; Choi, Junghoon; Valentine, Richard L

2002-02-01

76

Source Water Management for Disinfection By-Product Control using New York City's Operations Support Tool and On-Line Monitoring  

NASA Astrophysics Data System (ADS)

The United States Environmental Protection Agency's 2006 Stage 2 Disinfectant / Disinfection Byproduct Rule (DBPR) for finished drinking waters is intended to reduce overall DBP levels by limiting the levels of total trihalomethanes (TTHM) and five of the haloacetic acids (HAA5). Under Stage 2, maximum contaminant levels (MCLs), 80 ?g/L for TTHM and 60 ?g/L for HAA5, are based on a locational running annual average for individual sites instead of as the system-wide quarterly running annual average of the Stage 1 DBPR. This means compliance will have to be met at sampling locations of peak TTHM and HAA5 concentrations rather than an average across the entire system. Compliance monitoring under the Stage 2 DBPR began on April 1, 2012. The New York City (NYC) Department of Environmental Protection (DEP) began evaluating potential impacts of the Stage 2 DBPR on NYC's unfiltered water supply in 2002 by monitoring TTHM and HAA5 levels at various locations throughout the distribution system. Initial monitoring indicated that HAA5 levels could be of concern in the future, with the potential to intermittently violate the Stage 2 DBPR at specific locations, particularly those with high water age. Because of the uncertainty regarding the long-term prospect for compliance, DEP evaluated alternatives to ensure compliance, including operational changes (reducing chlorine dose, changing flow configurations to minimize water age, altering pH, altering source water withdrawals); changing the residual disinfectant from free chlorine to chloramines; and engineered treatment alternatives. This paper will discuss the potential for using DEP's Operations Support Tool (OST) and enhanced reservoir monitoring to support optimization of source water withdrawals to minimize finished water DBP levels. The OST is a state-of-the-art decision support system (DSS) to provide computational and predictive support for water supply operations and planning. It incorporates a water supply system simulation model (OASIS, HydroLogics, Inc.), reservoir water quality models, a near real-time monitoring network, and hydrologic forecasts to provide analytical support for both long-term planning and near-term operations. The OST helps managers and operators balance multiple objectives, including water supply reliability, water quality, and environmental and community release objectives. This paper will describe the results of initial testing to evaluate the potential to reduce DBP levels by managing source water withdrawals to minimize the transport of natural organic matter (NOM) precursors from upper reservoirs. Operating rules were developed that take advantage of selective withdrawal capabilities at some upstate reservoirs and the inherent flexibility of the overall water supply system, seeking to minimize DBPs within the larger framework of water supply, water quality, environmental, and regulatory objectives. The results demonstrated that there is substantial flexibility within the system to manage DBP levels, in some cases providing the potential for reductions of DBP precursors of nearly 10%. Additional research is underway that seeks to better understand the sources of natural organic matter in the NYC watershed to provide guidance for on-line monitoring to be used with the OST to support real-time operation support for DBP control.

Weiss, W. J.; Becker, W.; Schindler, S.

2012-12-01

77

Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) mixture toxicity to the macrophytes Myriophyllum spicatum and Myriophyllum sibiricum in aquatic microcosms.  

PubMed

Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) have been detected together in environmental water samples throughout the world. TCA may enter into aquatic systems via rainout as the degradation product of chlorinated solvents, herbicide use, as a by-product of water disinfection and from emissions of spent bleach liquor of kraft pulp mills. Sources of TFA include degradation of hydrofluorocarbons (HFCs) refrigerants and pesticides. These substances are phytotoxic and widely distributed in aquatic environments. A study to assess the risk of a binary mixture of TCA and TFA to macrophytes in aquatic microcosms was conducted as part of a larger study on haloacetic acids. M. spicatum and M. sibiricum were exposed to 0.1, 1, 3 and 10 mg/l of both TCA and TFA (neutralized with sodium hydroxide) in replicate (n = 3) 12000 l aquatic microcosms for 49 days in an one-way analysis of variance design. Each microcosm was stocked with 14 individual apical shoots per species. The plants were sampled at regular intervals and assessed for the somatic endpoints of plant length, root growth, number of nodes and wet and dry mass and the biochemical endpoints of chlorophyll-a, chlorophyll-b, carotenoid content and citric acid levels. Results indicate that there were statistically significant effects of the TCA/TFA mixture on certain pigment concentrations immediately after the start of exposure (2-7 days), but the plants showed no signs of stress thereafter. These data suggest that TCA/TFA mixtures at environmentally relevant concentrations do not pose a significant risk to these aquatic macrophytes. PMID:11878273

Hanson, Mark L; Sibley, Paul K; Mabury, Scott A; Solomon, Keith R; Muir, Derek C G

2002-02-21

78

Temporal variability in urinary levels of drinking water disinfection byproducts dichloroacetic acid and trichloroacetic acid among men.  

PubMed

Urinary haloacetic acids (HAAs), such as dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), have been suggested as potential biomarkers of exposure to drinking water disinfection byproducts (DBPs). However, variable exposure to and the short elimination half-lives of these biomarkers can result in considerable variability in urinary measurements, leading to exposure misclassification. Here we examined the variability of DCAA and TCAA levels in the urine among eleven men who provided urine samples on 8 days over 3 months. The urinary concentrations of DCAA and TCAA were measured by gas chromatography coupled with electron capture detection. We calculated the intraclass correlation coefficients (ICCs) to characterize the within-person and between-person variances and computed the sensitivity and specificity to assess how well single or multiple urine collections accurately determined personal 3-month average DCAA and TCAA levels. The within-person variance was much higher than the between-person variance for all three sample types (spot, first morning, and 24-h urine samples) for DCAA (ICC=0.08-0.37) and TCAA (ICC=0.09-0.23), regardless of the sampling interval. A single-spot urinary sample predicted high (top 33%) 3-month average DCAA and TCAA levels with high specificity (0.79 and 0.78, respectively) but relatively low sensitivity (0.47 and 0.50, respectively). Collecting two or three urine samples from each participant improved the classification. The poor reproducibility of the measured urinary DCAA and TCAA concentrations indicate that a single measurement may not accurately reflect individual long-term exposure. Collection of multiple urine samples from one person is an option for reducing exposure classification errors in studies exploring the effects of DBP exposure on reproductive health. PMID:25262085

Wang, Yi-Xin; Zeng, Qiang; Wang, Le; Huang, Yue-Hui; Lu, Zhi-Wei; Wang, Peng; He, Meng-Jie; Huang, Xin; Lu, Wen-Qing

2014-11-01

79

Rapid IC-ICP/MS method for simultaneous analysis of iodoacetic acids, bromoacetic acids, bromate, and other related halogenated compounds in water.  

PubMed

Haloacetic acids (HAAs) and bromate are toxic water disinfection by-products (DBPs) that the U.S. Environmental Protection Agency has regulated in drinking water. Iodoacetic acids (IAAs) are the emerging DBPs that have been recently found in disinfected drinking waters with higher toxicity than their corresponding chloro- and bromo-acetic acids. This study has developed a new rapid and sensitive method for simultaneous analysis of six brominated and four iodinated acetic acids, bromate, iodate, bromide, and iodide using ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS). Mono-, di- and tri-chloroacetic acids are not detected by this method because the sensitivity of ICP-MS analysis for chlorine is poor. Following IC separation, an Elan DRC-e ICP-MS was used for detection, with quantitation utilizing m/z of 79, 127, and 74 amu for Br, I, and Ge (optional internal standard) species, respectively. Although the primary method used was an external standard procedure, an internal standard method approach is discussed herein as well. Calibration and validation were done in a variety of natural and disinfection-treated water samples. The method detection limits (MDLs) in natural water ranged from 0.33 to 0.72 microg L(-1) for iodine species, and from 1.36 to 3.28 microg L(-1) for bromine species. Spiked recoveries were between 67% and 123%, while relative standard deviations ranged from 0.2% to 12.8% for replicate samples. This method was applied to detect the bromine and iodine species in drinking water, groundwater, surface water, and swimming pool water. PMID:19559915

Shi, Honglan; Adams, Craig

2009-07-15

80

Quality and Membrane Treatability of the Lake Houston Water Supply  

E-print Network

methane, dichlorobromo methane, and bromoform. 2 HAA5 denotes the sum of concentrations of monochloro-, dichloro-, trichloro-, monobromo-, and dibromo acetic acid. 3 HAA9 denotes the sum of HAA5 and concentrations of bromochloro-, dibromochloro... Protection Agency (USEPA) Method 551.1 (36). These DBPs consisted of four THMs (chloroform, bromodichloromethane, dibromochloromethane, and bromoform); four halacitonitriles or HANs (trichloro-, dichloro-, bromochloro-, and dibromoacetonitrile); two...

Chellam, Shankar; Sharma, Ramesh; Shetty, Grishma; Wei, Ying

2001-10-01

81

Amino acids  

MedlinePLUS

Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

82

Peracetic acid oxidation of saline waters in the absence and presence of H ?O ?: secondary oxidant and disinfection byproduct formation.  

PubMed

Peracetic acid (PAA) is a disinfectant considered for use in ballast water treatment, but its chemical behavior in such systems (i.e., saline waters) is largely unknown. In this study, the reactivity of PAA with halide ions (chloride and bromide) to form secondary oxidants (HOCl, HOBr) was investigated. For the PAA-chloride and PAA-bromide reactions, second-order rate constants of (1.47 ± 0.58) × 10(-5) and 0.24 ± 0.02 M(-1) s(-1) were determined for the formation of HOCl or HOBr, respectively. Hydrogen peroxide (H2O2), which is always present in PAA solutions, reduced HOCl or HOBr to chloride or bromide, respectively. As a consequence, in PAA-treated solutions with [H2O2] > [PAA], the HOBr (HOCl) steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs). HOI (formed from the PAA-iodide reaction) affected this process because it can react with H2O2 back to iodide. H2O2 is thus consumed in a catalytic cycle and leads to less efficient HOBr scavenging at even low iodide concentrations (<1 ?M). In PAA-treated solutions with [H2O2] < [PAA] and high bromide levels, mostly brominated DBPs are formed. In synthetic water, bromate was formed from the oxidation of bromide. In natural brackish waters, bromoform (CHBr3), bromoacetic acid (MBAA), dibromoacetic acid (DBAA), and tribromoacetic acid (TBAA) formed at up to 260, 106, 230, and 89 ?g/L, respectively for doses of 2 mM (ca. 150 mg/L) PAA and [H2O2] < [PAA]. The same brackish waters, treated with PAA with [H2O2] ? [PAA], similar to conditions found in commercial PAA solutions, resulted in no trihalomethanes and only low haloacetic acid concentrations. PMID:25611970

Shah, Amisha D; Liu, Zheng-Qian; Salhi, Elisabeth; Höfer, Thomas; von Gunten, Urs

2015-02-01

83

Thermolysis of fluoropolymers as a potential source of halogenated organic acids in the environment.  

PubMed

Following the introduction of hydrochlorofluorocarbon (HCFCs) and hydrofluorocarbon (HFCs) gases as replacements for the ozone-destroying chlorofluorocarbons (CFCs), it has been discovered that HCFCs/HFCs can degrade in the atmosphere to produce trifluoroacetic acid, a compound with no known loss mechanisms in the environment, and higher concentrations in natural waters have been shown to be mildly phytotoxic. Present environmental levels of trifluooracetic acid are not accounted by HCFC/HFC degradation alone. Here we report that thermolysis of fluorinated polymers, such as the commercial polymers Teflon and Kel-F, can also produce trifluoroacetate and the similar compound chlorodifluoroacetate. This can occur either directly, or indirectly via products that are known to degrade to these haloacetates in the atmosphere. The environmental significance of these findings is confirmed by modelling, which indicates that the thermolysis of fluoropolymers in industrial and consumer high-temperature applications (ovens, non-stick cooking utensils and combustion engines) is likely to be a significant source of trifluoroacetate in urban rain water ( approximately 25 ng l-1, as estimated for Toronto). Thermolysis also leads to longer chain polyfluoro- and/or polychlorofluoro- (C3-C14) carboxylic acids which may be equally persistent. Some of these products have recently been linked with possible adverse health and environmental impacts and are being phased out of the US market. Furthermore, we detected CFCs and fluorocarbons-groups that can destroy ozone and act as greenhouse gases, respectively-among the other thermal degradation products, suggesting that continued use of fluoropolymers may also exacerbate stratospheric ozone-depletion and global warming. PMID:11460160

Ellis, D A; Mabury, S A; Martin, J W; Muir, D C

2001-07-19

84

Field level evaluation and risk assessment of the toxicity of dichloroacetic acid to the aquatic macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum.  

PubMed

Dichloroacetic acid (DCA), a haloacetic acid, is a common contaminant of aquatic ecosystems. A study to investigate potential phytotoxic effects on rooted and floating macrophytes (Myriophyllum spicatum, M. sibiricum, and Lemna gibba) was conducted. Replicate 12,000 L outdoor microcosms (n = 3) were treated with 3, 10, 30, and 100 mg/L of DCA that had been neutralized to the sodium salt, plus controls. Plants were sampled regularly over 21 days and assessed for a variety of endpoints including plant growth, root growth, number of nodes, wet and dry mass, chlorophyll-a, chlorophyll-b, carotenoids, and citrate levels. EC10, EC25, and EC50 values were calculated for each endpoint that exhibited a concentration-response. Overall, M. sibiricum was slightly more sensitive than M. spicatum to DCA exposure. The most sensitive plant endpoints were wet mass and plant length. Pigments showed no response with exposure to DCA. The probability of current concentrations of DCA in Canadian lake water and Swiss river waters exceeding thresholds of toxicity derived from single species effect measure distributions (EC10s) is < 0.01%. The use of effect measure distributions holds promise as a new risk assessment technique for aquatic plants. Currently, environmental levels of DCA do not pose a risk to these plants. PMID:12706393

Hanson, Mark L; Sibley, Paul K; Mabury, Scott A; Muir, Derek C G; Solomon, Keith R

2003-05-01

85

Folic Acid  

MedlinePLUS

Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

86

Folic Acid  

MedlinePLUS

Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

87

Aspartic acid  

MedlinePLUS

... don't get this amino acid from the food we eat. Aspartic acid is also called asparaginic acid. Aspartic acid helps every cell in the body work. It plays a role in: Hormone production and release Normal nervous system function Plant sources ...

88

Acid Rain.  

ERIC Educational Resources Information Center

Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

Openshaw, Peter

1987-01-01

89

The effect of UV/H2O2 treatment on disinfection by-product formation potential under simulated distribution system conditions.  

PubMed

Advanced oxidation with ultraviolet light and hydrogen peroxide (UV/H(2)O(2)) produces hydroxyl radicals that have the potential to degrade a wide-range of organic micro-pollutants in water. Yet, when this technology is used to reduce target contaminants, natural organic matter can be altered. This study evaluated disinfection by-product (DBP) precursor formation for UV/H(2)O(2) while reducing trace organic contaminants in natural water (>90% for target pharmaceuticals, pesticides and taste and odor producing compounds and 80% atrazine degradation). A year-long UV/H(2)O(2) pilot study was conducted to evaluate DBP precursor formation with varying water quality. The UV pilot reactors were operated to consistently achieve 80% atrazine degradation, allowing comparison of low pressure (LP) and medium pressure (MP) lamp technologies for DBP precursor formation. Two process waters of differing quality were used as pilot influent, i.e., before and after granular activated carbon adsorption. DBP precursors increased under most of the conditions studied. Regulated trihalomethane formation potential increased through the UV/H(2)O(2) reactors from 20 to 118%, depending on temperature and water quality. When Post-GAC water served as reactor influent, less DBPs were produced in comparison to conventionally treated water. Haloacetic acid (HAA5) increased when conventionally treated water served as UV/H(2)O(2) pilot influent, but only increased slightly (MP lamp) when GAC treated water served as pilot influent. No difference in 3-day simulated distribution system DBP concentration was observed between LP and MP UV reactors when 80% atrazine degradation was targeted. PMID:21624627

Metz, D H; Meyer, M; Dotson, A; Beerendonk, E; Dionysiou, D D

2011-07-01

90

The formation and control of disinfection by-products using chlorine dioxide  

Microsoft Academic Search

In this study, chlorine dioxide (ClO2) was used as an alternative disinfectant with vanillic acid, p-hydroxybenzoic acid, and humic acid as the organic precursors in a natural aquatic environment. The primary disinfection by-products (DBPs) formed were trihalomethanes (THMs) and haloacetic acids (HAAs). Under neutral conditions (pH=7) for vanillic acid, more total haloacetic acids (THAAs) than total trihalomethanes (TTHMs) were found,

Chen-Yu Chang; Yung-Hsu Hsieh; I-Chen Shih; Shen-Sheng Hsu; Kuo-Hua Wang

2000-01-01

91

Acidity in bile acid systems  

Microsoft Academic Search

The acidity parameter in bile acid systems was re-examined in an attempt to unify the many contrasting results reported in the literature. Discrepancies originate not only through differences in experimental approaches but mainly through the peculiar behaviour of bile acids and their salts, which can be present in aqueous solution as monomers, or simple and\\/or mixed aggregates. The acidity (and

Adamo Fini; Giorgio Feroci; Aldo Roda

2002-01-01

92

Ascorbic Acid  

MedlinePLUS

Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

93

Ethacrynic Acid  

MedlinePLUS

Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

94

Folic acid  

MedlinePLUS

Folic acid is a water-soluble B vitamin. Since 1998, it has been added to cold cereals, flour, breads, ... law. Foods that are naturally high in folic acid include leafy vegetables (such as spinach, broccoli, and ...

95

Mefenamic Acid  

MedlinePLUS

Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

96

Aristolochic Acids  

Cancer.gov

Aristolochic acids are a group of acids found naturally in many types of plants known as Aristolochia (birthworts or pipevines) and some types of plants known as Asarum (wild ginger), which grow worldwide.

97

Aristolochic Acids  

MedlinePLUS

... Sciences NIH-HHS www.niehs.nih.gov Aristolochic Acids Key Points Report on Carcinogens Status Known to be human carcinogens Aristolochia Clematitis Aristolochic Acids n Known human carcinogens n Found in certain ...

98

Aminocaproic Acid  

MedlinePLUS

Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

99

Folic Acid  

MedlinePLUS

... acid. Talk to your doctor about how much folic acid you need if you: Are taking medicines used to treat: Epilepsy Type 2 diabetes Rheumatoid arthritis , lupus , psoriasis , asthma , and inflammatory bowel disease Have kidney disease ...

100

Valproic Acid  

MedlinePLUS

Valproic acid is used alone or with other medications to treat certain types of seizures. Valproic acid is also used to treat mania (episodes of ... to relieve headaches that have already begun. Valproic acid is in a class of medications called anticonvulsants. ...

101

Shikimic Acid  

NSDL National Science Digital Library

The molecule for this month comes from the article Isolation of Shikimic Acid from Star Aniseed by Richard Payne and Michael Edmonds. Shikimic acid plays a key role in the biosynthesis of many important natural products including aromatic amino acids, alkaloids, phenolics, and phenylpropanoids. It plays such an important role that one of the key biosynthetic pathways is referred to as the shikimate pathway.

102

Use of urinary trichloroacetic acid as an exposure biomarker of disinfection by-products in cancer studies.  

PubMed

Urinary trichloroacetic acid (TCAA) has been proposed as a valid exposure biomarker for ingested disinfection by-products (DBP) for reproductive studies. However, it has never been used in epidemiologic studies on cancer. We investigate the performance of urinary TCAA as a biomarker of DBP exposure in the framework of an epidemiologic study on cancer. We conducted home visits to collect tap water, first morning void urine, and a 48h fluid intake diary among 120 controls from a case-control study of colorectal cancer in Barcelona, Spain. We measured urine TCAA and creatinine, and 9 haloacetic acids and 4 trihalomethanes (THM) in tap water. Lifetime THM exposure was estimated based on residential history since age 18 plus routine monitoring data. Robust linear regressions were used to estimate mean change in urinary TCAA adjusted by covariates. Among the studied group, mean age was 74 years (range 63-85) and 41 (34%) were females. Mean total tap water consumption was 2.2l/48h (standard error, 0.1l/48h). Geometric mean urine TCAA excretion rate was 17.3pmol/min [95%CI: 14.0-21.3], which increased 2% for a 10% increase in TCAA ingestion and decreased with total tap water consumption (-17%/l), water intake outside home (-32%), plasmatic volume (-64%/l), in smokers (-79%), and in users of non-steroidal anti-inflammatory drugs (-50%). Urinary TCAA levels were not associated with lifetime THM exposure. In conclusion, our findings support that urine TCAA is not a valid biomarker in case-control studies of adult cancer given that advanced age, comorbidites and medication use are prevalent and are determinants of urine TCAA levels, apart from ingested TCAA levels. In addition, low TCAA concentrations in drinking water limit the validity of urine TCAA as an exposure biomarker. PMID:25462676

Salas, Lucas A; Gracia-Lavedan, Esther; Goñi, Fernando; Moreno, Victor; Villanueva, Cristina M

2014-11-01

103

Basically Acids  

NSDL National Science Digital Library

Students learn the basics of acid/base chemistry in a fun, interactive way by studying instances of acid/base chemistry found in popular films such as Harry Potter and the Prisoner of Azkaban and National Treasure. Students learn what acids, bases and indicators are and how they can be used, including invisible ink. They also learn how engineers use acids and bases every day to better our quality of life. Students' interest is piqued by the use of popular culture in the classroom.

2014-09-18

104

Acid Rain  

Microsoft Academic Search

Measurements of the acidity of rain and snow reveal that in parts of the eastern U.S. and of western Europe precipitation has changed from a nearly neutral solution 200 years ago to a dilute solution of sulfuric and nitric acids today. The trend is a result of the emission of sulfur and nitrogen oxides to the atmosphere accompanying the rise

Gene E. Likens; Richard F. Wright; James N. Galloway; Thomas J. Butler

1979-01-01

105

Acid rain  

SciTech Connect

This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

White, J.C. (Cornell University, Ithaca, NY (US))

1988-01-01

106

Acid rain  

SciTech Connect

This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

Elsworth, S.

1985-01-01

107

Domoic Acid  

NSDL National Science Digital Library

This online student report discusses the chemistry of domoic acid, a biotoxin that is produced by the diatom Psuedo-nitzschia and associated with Amnesiac Shellfish Poisoning (ASP). In addition to a descriptive summary and images, the report links to other areas of interest related to domoic acid poisoning including signs and symptoms, modes of action, and treatment.

Bailey, Christina

108

Acids (GCMP)  

NSDL National Science Digital Library

Acids: this is a resource in the collection "General Chemistry Multimedia Problems". We will observe the reaction of sodium bicarbonate with three acid solutions. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

109

Acid Precipitation  

NSDL National Science Digital Library

Acid precipitation will be defined. At different points in the lesson students will write balanced reactions for the formation acid precipitation from atmospheric sulfur and nitrogen oxides and the neutralization of acids by limestone. Students will determine which states are most at risk from acid precipitation and assess how that risk has changed from 1996 to 2006. Sources of atmospheric sulfur (burning of high-sulfur coal) and nitrogen oxides (automobile exhaust) will be listed. The buffering effect of limestone soils and its mitigating effect on acid precipitation will be discussed. Students will correlate these areas with sulfur and nitrogen oxide production, population, composition of coal fields, and soil composition. This resource includes both a teaching guide and student worksheets.

Tyser, Jim

110

Acid Rain  

NSDL National Science Digital Library

Due to the presence of dissolved gases such as carbon dioxide, rainfall is naturally acidic. The release of other gases and chemicals such as sulfur dioxide during the combustion of coal and oil can cause rainfall to become even more acidic, sometimes to the point of toxicity. In this activity, students will measure the pH of local rainfall to see what effect these gases have in their region. They will also check an online resource to see how the releases of acid rain-causing chemicals have varied over the past 20 years, and answer questions about the information they uncover.

Chris Fox

111

ACID RAIN  

EPA Science Inventory

Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating diff...

112

Acid Reflux  

MedlinePLUS

... time. This stomach juice consists of acid, digestive enzymes, and other injurious materials. The prolonged contact of ... role in absorption of vitamins (Vitamin B12), the digestion of proteins, and initiation of peristalsis which causes the food ...

113

Acidic precipitation  

SciTech Connect

At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

Martin, H.C.

1987-01-01

114

Acidizing wells  

Microsoft Academic Search

A method of increasing the permeability of a rock formation by acidizing is applicable to silicate-bearing formations containing alkaline-earth-metal ions and alkali- metal ions which would have a reducing effect on the permeability of the formation. A carbonate solution is injected into the formation to convert any calcium sulfate to calcium carbonate. This is followed by injecting hydrochloric acid to

1966-01-01

115

DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON  

EPA Science Inventory

The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by-products (DBPS) including total organic halide, trihalomethanes, haloacetic acids, haloacentonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along with ...

116

EARLY CRANIOFACIAL DEVELOPMENT: LIFE AMONG THE SIGNALS  

EPA Science Inventory

Early Craniofacial Development: Life Among the Signals. Sid Hunter and Keith Ward. Reproductive Toxicology Division, NHEERL, US EPA, RTP, NC, 27711 Haloacetic acids (HAA) are chemicals formed during drinking water disinfection and present in finished tap water. Exposure o...

117

QUENCHING OF CHLORINATION DISINFECTION BY-PRODUCT FORMATION IN DRINKING WATER BY HYDROGEN PEROXIDE. (R825362)  

EPA Science Inventory

Reactions between chlorine disinfectants, dissolved organic matter, and other chemicals in water form a series of disinfection by-products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs), that are toxic and subject to increasingly stringent regulations. Th...

118

IDENTIFICATION OF CHLORINE DIOXIDE DRINKING WATER DISINFECTION BY-PRODUCTS FORMED AT HIGH BROMIDE LEVELS  

EPA Science Inventory

Due to concern over the potential adverse health effects of trihalomethanes (THMs), haloacetic acids, and other chlorinated by-products in chlorinated drinking water, alternative disinfection methods are being explored. Chlorine dioxide is a popular alternative, with over 500 dri...

119

FEASIBILITY STUDY OF THE UTILITY OF THE ICR DATABASE FOR STUDYING THE REPRODUCTIVE EFFECTS OF DISINFECTION BY-PRODUCTS IN DRINKING WATER  

EPA Science Inventory

This study assessed the feasibility of conducting an epidemiologic study of the relationship between DBPs and adverse reproductive outcomes, using quarterly monitoring data of trihalomethanes and haloacetic acids from the EPA's Information Collection Rule (ICR) data base. Emphas...

120

DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON  

EPA Science Inventory

The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

121

Uric acid - urine  

MedlinePLUS

The urine uric acid test measures the level of uric acid in urine. Uric acid level can also be checked using a blood ... to choose the best medicine to lower uric acid level in the blood. Uric acid is a ...

122

Salicylic acids  

PubMed Central

Salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. The area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. The skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under the prevailing external conditions. The metabolic status that allows the host invasion either as pathogenesis or symbiosis with possible intermediary stages in close systems has been tried to underpin here. PMID:22301975

Hayat, Shamsul; Irfan, Mohd; Wani, Arif; Nasser, Alyemeni; Ahmad, Aqil

2012-01-01

123

Acid Stomach  

NSDL National Science Digital Library

This Science NetLinks lesson is intended for a high-school, introductory chemistry class or health class. The lesson begins with an article on the history of the development of aspirin. Students will then complete a lab that compares the reaction of regular aspirin, buffered aspirin, and enteric aspirin in neutral, acidic, and basic solutions. They will then analyze the results of the experiment to gain insight into how this information was used by researchers to solve some of the problems associated with aspirin. To complete the lesson, students must understand acids and bases.

Science Netlinks

2003-08-07

124

Acid Rain  

NSDL National Science Digital Library

This activity is part of Planet Diary and is an online examination into acid rain and sulfur dioxide emissions. Students research which states have succeeded in reducing sulfur dioxide emissions between 1980 and 1999, and which states emissions have increased. This activity is accompanied by a page of websites for further information.

125

Acid rain  

SciTech Connect

An overview is presented of acid rain and the problems it causes to the environment worldwide. The acidification of lakes and streams is having a dramatic effect on aquatic life. Aluminum, present in virtually all forest soils, leaches out readily under acid conditions and interferes with the gills of all fish, some more seriously than others. There is evidence of major damage to forests in European countries. In the US, the most severe forest damage appears to be in New England, New York's Adirondacks, and the central Appalachians. This small region is part of a larger area of the Northeast and Canada that appears to have more acid rainfall than the rest of the country. It is downwind from major coal burning states, which produce about one quarter of US SO/sub 2/ emissions and one sixth of nitrogen oxide emissions. Uncertainties exist over the causes of forest damage and more research is needed before advocating expensive programs to reduce rain acidity. The President's current budget seeks an expansion of research funds from the current $30 million per year to $120 million.

Not Available

1984-06-01

126

Amino Acids  

NSDL National Science Digital Library

The Featured Molecules this month are the 20 standard ?-amino acids found in proteins and serve as background to the paper by Barone and Schmidt on the Nonfood Applications of Proteinaceous Renewable Materials. The molecules are presented in two formats, the neutral form and the ionized form found in solution at physiologic pH.

127

Acid Attack  

NSDL National Science Digital Library

In this activity, students explore the effect of chemical erosion on statues and monuments. They use chalk to see what happens when limestone is placed in liquids with different pH values. They also learn several things that engineers are doing to reduce the effects of acid rain.

Integrated Teaching and Learning Program,

128

Pharmacology of oleanolic acid and ursolic acid  

Microsoft Academic Search

Oleanolic acid and ursolic acid are triterpenoid compounds that exist widely in food, medicinal herbs and other plants. This review summarizes the pharmacological studies on these two triterpenoids. Both oleanolic acid and ursolic acid are effective in protecting against chemically induced liver injury in laboratory animals. Oleanolic acid has been marketed in China as an oral drug for human liver

Jie Liu

1995-01-01

129

Domoic Acid  

NSDL National Science Digital Library

This highly detailed chemical information page features domoic acid, a toxin associated with Amnesic shellfish poisoning and naturally produced by the red algae Chondria armata and diatoms of the genus Pseudo-nitzschia. Created by the International Programme on Chemical Safety, this web page organizes information under the following sections: Name, Summary, Physio-Chemical Properties, Uses, Routes of Entry, Kinetics, Toxicology, Toxicological and Biomedical Investigations, Clinical Effects, Management, Illustrative Cases, Additional Information, References, and Authors.

INCHEM

130

Methylmalonic acid blood test  

MedlinePLUS

... acid is a substance produced when proteins (called amino acids) in the body break down. A test can ... Cederbaum S, Berry GT. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Devaskar ...

131

Folic acid - test  

MedlinePLUS

Folic acid is a type of B vitamin. This article discusses the test to measure the amount of folic acid in the blood. ... that may interfere with test results, including folic acid supplements. Drugs that can decrease folic acid measurements ...

132

Acid Ocean  

NSDL National Science Digital Library

The I2I-Acid Ocean virtual lab is an e-learning activity where students become virtual scientists studying the impact of ocean acidification on sea urchin larval growth. Students recreate a real, up-to-date climate change experiment. They also learn important general scientific principles, such as the importance of sample size and numbers of replicates, and discuss what this research into a specific impact of climate change may mean for the future of our oceans. There is a French translation available.

133

Understanding Acid Rain  

ERIC Educational Resources Information Center

The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

Damonte, Kathleen

2004-01-01

134

Brnsted Acids The Strongest Isolable Acid**  

E-print Network

-Chan Kim, and Christopher A. Reed* Acids based on carborane anions as conjugate bases (Figure 1) are a newBrønsted Acids The Strongest Isolable Acid** Mark Juhasz, Stephan Hoffmann, Evgenii Stoyanov, Kee class of Brønsted (protic) acids, notable for their "strong yet gentle" qualities.[1] For example

Reed, Christopher A.

135

Acid rain  

SciTech Connect

Acid rain, says Boyle is a chemical leprosy eating into the face of North America and Europe, perhaps the major ecological problem of our time. Boyle describes the causes and scope of the phenomenon; the effects on man, wildlife, water, and our cultural heritage. He probes the delays of politicians and the frequent self-serving arguments advanced by industry in the face of what scientists have proved. The solutions he offers are to strengthen the Clean Air Act and require emission reductions that can be accomplished by establishing emission standards on a regional or bubble basis, burn low-sulfur coal, install scrubbers at critical plants, and invest in alternative energy sources. 73 references, 1 figure.

Boyle, R.H.; Boyle, R.A.

1983-01-01

136

Acanthoic acid  

PubMed Central

The title compound [systematic name: (1R,4aR,7S,8aS,10aS)-1,4a,7-trimethyl-7-vinyl-1,2,3,4,4a,6,7,8,8a,9,10,10a-dodeca­hydro­phenanthrene-1-carb­oxy­lic acid], C20H30O2, is a pimarane-type diterpene extracted from Croton oblongifolius. There are two independent mol­ecules in the asymmetric unit. In both of these, the six-membered rings A, B and C adopt chair, boat and half-chair conformations, respectively. Rings A and B are trans-fused. The two mol­ecules in the asymmetric unit form O—H?O hydrogen-bonded R 2 2(8) dimers. The absolute configuration was assigned on the basis of the published literature on analogous structures. PMID:21587780

Suwancharoen, Sunisa; Tommeurd, Wantanee; Phurat, Chuttree; Muangsin, Nongnuj; Pornpakakul, Surachai

2010-01-01

137

Bioactive Fatty Acids  

Technology Transfer Automated Retrieval System (TEKTRAN)

Oxygenated fatty acids are useful as specialty chemicals, plasticizers, and biomedicals. Microbial enzymes convert fatty acids to mono-, di-, and trihydroxy fatty acid products. Among them, Bacillus megaterium ALA2 converted n-6 and n-3 PUFAs to many new oxygenated fatty acids. Linoleic acid was ...

138

Plasma amino acids  

MedlinePLUS

Amino acids blood test ... types of methods used to determine the individual amino acids levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

139

Uric acid test (image)  

MedlinePLUS

Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

140

Stomach acid test  

MedlinePLUS

Gastric acid secretion test ... of the cells in the stomach to release acid, a hormone called gastrin may be injected into ... 3.5). These numbers are converted to actual acid production in units of milliequivalents per hour in ...

141

Folic Acid and Pregnancy  

MedlinePLUS

... Flu Pregnancy Precautions Checkups: What to Expect Folic Acid and Pregnancy KidsHealth > Parents > Pregnancy & Newborn Center > Your ... before conception and during early pregnancy . About Folic Acid Folic acid, sometimes called folate, is a B ...

142

Facts about Folic Acid  

MedlinePLUS

... Information For... Media Policy Makers Facts About Folic Acid Language: English Español (Spanish) Recommend on Facebook Tweet ... of the baby's brain and spine. About folic acid Folic acid is a B vitamin. Our bodies ...

143

Azelaic Acid Topical  

MedlinePLUS

Azelaic acid gel is used to clear the bumps, lesions, and swelling caused by rosacea (a skin disease that ... redness, flushing, and pimples on the face). Azelaic acid cream is used to treat acne. Azelaic acid ...

144

Acid Lipase Disease  

MedlinePLUS

NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, Wolman’s Disease Table of Contents (click to jump ... research is being done? Clinical Trials What is Acid Lipase Disease ? Acid lipase disease occurs when the ...

145

Valproic Acid and Pregnancy  

MedlinePLUS

... visit us online at: www.OTISpregnancy.org . Valproic acid and Pregnancy In every pregnancy, a woman starts ... from your health care professional. What is valproic acid? Valproic acid is a medication commonly used to ...

146

Method of acidizing wells using gelled acids  

SciTech Connect

The permeability of siliceous or calcareous subterranean formations adjacent a wellbore is increased by contacting the formation with a gelled aqueous acid capable of dissolving mineral constituents in the formation. The gelled aqueous acid compositions comprise (a) aqueous hydrochloric acid, and (b) a readily soluble gelling agent. Component (b) contains a sufficient amount of a polyoxyethylene glycol to gel the acid and enough ammonium-, alkali-, or alkaline earth metal bicarbonate or carbonate to cause rapid dissolution and dispersion of the polyoxyethylene glycol in the aqueous hydrochloric acid.

Crowe, C.W.

1984-01-17

147

Acid Rain Study Guide.  

ERIC Educational Resources Information Center

Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid

Hunger, Carolyn; And Others

148

Acid-Base Equilibria  

NSDL National Science Digital Library

This 9-page PDF document is part of an environmental geochemistry course taught by Dr. David Sherman at the University of Bristol. Topics include acid-base theories, aqueous systems, strong and weak acids and bases, acid-base properties of minerals, the pH of weak acid and buffered systems, and the calculation of titration curves.

David W. Sherman

149

Acid tolerance in amphibians  

SciTech Connect

Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities. Amphibians as a group appear to be relatively acid tolerant, with many species suffering increased mortality only below pH 4. However, amphibians exhibit much intraspecific variation in acid tolerance, and some species are sensitive to even low levels of acidity. Furthermore, nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.

Pierce, B.A.

1985-04-01

150

Acetylenic acids from mosses.  

PubMed

Two new acetylenic fatty acids, 9, 12-octadecadien-6-ynoic and 11, 14-eicosadien-8-ynoic, were identified from lipids of the moss, Fontinalis antipyretica. They resemble the previously identified 9,12,15-octadecatrien-6-ynoic acid by having a methylene interrupted unsaturated system. The C20 acetylenic acid shows that the capability of mosses to synthesize polyolefinic acids of this chain length applies, in certain species, also to olefinic-acetylenic acids. PMID:1160525

Anderson, W H; Gellerman, J L; Schlenk, H

1975-08-01

151

Acids and Bases (Netorials)  

NSDL National Science Digital Library

Acids and Bases: this is a resource in the collection "Netorials". In this module there is an introduction to the chemical properties of acids and bases. Afterwards, the sections include topics such as Molecular Structures of Acids and Bases, Ionization constants, properties of salts, buffers and Lewis theory of Acids and Bases. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

152

New bioactive fatty acids.  

PubMed

Many oxygenated fatty acids are bioactive compounds. Nocardia cholesterolicum and Flavobacterium DS5 convert oleic acid to 10 hydroxy stearic acid and linoleic acid to 10-hydroxy-12(Z)-octadecanoic acid. Pseudomonas aeruginosa PR3 converts oleic acid to the new compounds, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) through 10-hydroxy-8-octadecenoic acid, and racinoleic acid to 7,10,12-trihydroxy-8-octadecenoic acid. DOD showed antibacterial activity including against food-borne pathogens. Bacillus megaterium ALA2 converted n-6 and n-3 PUFAs to many new oxygenated fatty acids. For example: linoleic acid was converted to12,13-epoxy-9-octadecenoic acid and then to 12,13-dihydroxy-9-octadecenoic acid (12,13-DHOA). From here, there are two bioconversion pathways. The major pathway is: 12,13-DHOA --> 12,13,17-trihydroxy-9(S)-octadecenoic acid (THOA) --> 12,17;13,17-diepoxy-16-hydroxy-9(Z)-octadecenoic acid (DEOA) --> 7-hydroxy-DEOA. The minor pathway is: 12,13-DHOA --> 12,13,16-THOA --> 12-hydroxy-13,16-epoxy-9(Z)-octadecenoic acid. 12,13,17-THOA has anti-plant pathogenic fungal activity. The tetrahydrofuranyl moiety is known in anti cancer drugs. Strain ALA2 also converts other n-3 and n-6 PUFAs such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) to many new oxygenated unsaturated fatty acid products. All of these new products have high potential for antimicrobial agents or biomedical applications. We also screened 12 Mortierella fungal strains from the ARS Culture Collection for the production of bioactive fatty acids such as dihomo-gama-linolenic acid (DGLA) and arachidonic acid. All of the strains tested produced AA and DGLA from glucose or glycerol. The top five AA producers (mg AA/g CDW) were in the following order: M. alpina > M. zychae > M. hygrophila > M. minutissima > M. parvispora. Both AA and DGLA are important natural precursors of a large family of prostaglandin and thromboxane groups. PMID:18296335

Hou, Ching T

2008-01-01

153

Acid Thunder: Acid Rain and Ancient Mesoamerica  

ERIC Educational Resources Information Center

Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

Kahl, Jonathan D. W.; Berg, Craig A.

2006-01-01

154

Purification of oleic acid and linoleic acid  

SciTech Connect

To permit kinetic studies of the reactivity of unsaturated fatty acids towards oxygen radicals, it is essential to remove traces of hydroperoxides and other conjugated lipid impurities commonly present in commercial samples. Removal of these impurities has been satisfactorily achieved for oleic and linoleic acids by anaerobic low temperature recrystallization from acetonitrile. The uv spectra of commercial and purified samples are compared.

Arudi, R.L.; Sutherland, M.W.; Bielski, B.H.J.

1983-01-01

155

Purification of oleic acid and linoleic acid  

Microsoft Academic Search

To permit kinetic studies of the reactivity of unsaturated fatty acids towards oxygen radicals, it is essential to remove traces of hydroperoxides and other conjugated lipid impurities commonly present in commercial samples. Removal of these impurities has been satisfactorily achieved for oleic and linoleic acids by anaerobic low temperature recrystallization from acetonitrile. The uv spectra of commercial and purified samples

R. L. Arudi; M. W. Sutherland; B. H. J. Bielski

1983-01-01

156

Sulfuric acid poisoning  

MedlinePLUS

Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and ... or mucous membranes. This article discusses poisoning from sulfuric acid. This is for information only and not for ...

157

Uric acid - blood  

MedlinePLUS

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some ... dried beans and peas, and beer. Most uric acid dissolves in blood and travels to the kidneys. ...

158

Folic Acid Quiz  

MedlinePLUS

... Global Activities Information For... Media Policy Makers Folic Acid Quiz Language: English Español (Spanish) Recommend on Facebook ... button beside the question. Good Luck! 1. Folic acid is: A a B vitamin B a form ...

159

Zoledronic Acid Injection  

MedlinePLUS

Zoledronic acid (Reclast) is used to prevent or treat osteoporosis (condition in which the bones become thin and weak ... of life,' end of regular menstrual periods). Zoledronic acid (Reclast) is also used to treat osteoporosis in ...

160

Aminocaproic Acid Injection  

MedlinePLUS

Aminocaproic acid injection is used to control bleeding that occurs when blood clots are broken down too quickly. This ... the baby is ready to be born). Aminocaproic acid injection is also used to control bleeding in ...

161

Hydrochloric acid poisoning  

MedlinePLUS

Hydrocholoric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe damage, such ... poisoning due to swallowing or breathing in hydrochloric acid. This is for information only and not for ...

162

Acid-fast stain  

MedlinePLUS

The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body ... dye. The slide is then washed with an acid solution and a different stain is applied. Bacteria ...

163

Alpha Hydroxy Acids  

MedlinePLUS

... page Home Cosmetics Products & Ingredients Ingredients Alpha Hydroxy Acids See also: Guidance for Industry: Labeling for Cosmetics Containing Alpha Hydroxy Acids The following information is intended to answer questions ...

164

Methylmalonic Acid Test  

MedlinePLUS

... this website will be limited. Search Help? Methylmalonic Acid Share this page: Was this page helpful? Also known as: MMA Formal name: Methylmalonic Acid Related tests: Vitamin B12 and Folate , Homocysteine , Intrinsic ...

165

Aminolevulinic Acid Topical  

MedlinePLUS

Aminolevulinic acid is used in combination with photodynamic therapy (PDT; special blue light) to treat actinic keratoses (small crusty ... skin cancer) of the face or scalp. Aminolevulinic acid is in a class of medications called photosensitizing ...

166

Carbolic acid poisoning  

MedlinePLUS

Phenol poisoning; Phenylic acid poisoning; Hydroxybenzene poisoning; Phenic acid poisoning; Benzenol poisoning ... Phenol ... and Disease Registry (ATSDR). 2008. Toxicological profile for Phenol. Atlanta, GA: U.S. Department of Health and Human ...

167

Lactic acid test  

MedlinePLUS

Lactate test ... test. Exercise can cause a temporary increase in lactic acid levels. ... not getting enough oxygen. Conditions that can increase lactic acid levels include: Heart failure Liver disease Lung disease ...

168

Acid (and Base) Rainbows  

NSDL National Science Digital Library

Learners use red cabbage juice and pH indicator paper to test the acidity and basicity of household materials. The activity links this concept of acids and bases to acid rain and other pollutants. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.

2014-06-27

169

The Acid Rain Reader.  

ERIC Educational Resources Information Center

A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

Stubbs, Harriett S.; And Others

170

Neutralizing Acids and Bases  

NSDL National Science Digital Library

Learners use their knowledge of color changes with red cabbage indicator to neutralize an acidic solution with a base and then neutralize a basic solution with an acid. Use this as a follow-up activity to the related activity, "Color Changes with Acids and Bases."

2012-04-08

171

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

172

What Is Acid Rain?  

ERIC Educational Resources Information Center

Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

Likens, Gene E.

2004-01-01

173

Amino acid analysis  

NASA Technical Reports Server (NTRS)

The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

Winitz, M.; Graff, J. (inventors)

1974-01-01

174

Cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Waunakee, WI); Lyamichev, Victor I. (Madison, WI); Brow; Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2010-11-09

175

Cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2000-01-01

176

Cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor L. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2007-12-11

177

Editorial: Acid precipitation  

SciTech Connect

This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

NONE

1995-09-01

178

Nucleic acid detection assays  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

2005-04-05

179

Acetylenic acids from mosses  

Microsoft Academic Search

Two new acetylenic fatty acids, 9, 12-octadecadien-6-ynoic and 11,14-eicosadien-8-ynoic, were identified from lipids of the\\u000a moss,Fontinalis antipyretica. They resemble the previously identified 9,12,15-octadecatrien-6-ynoic acid by having a methylene interrupted unsaturated\\u000a system. The C20 acetylenic acid shows that the capability of mosses to synthesize polyolefinic acids of this chain length applies, in certain\\u000a species, also to olefinic-acetylenic acids.

W. H. Anderson; J. L. Gellerman

1975-01-01

180

Nucleic acid detection compositions  

SciTech Connect

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

2008-08-05

181

Process for the preparation of lactic acid and glyceric acid  

DOEpatents

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02

182

Nucleic acid detection kits  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

2005-03-29

183

[Biosynthesis of adipic acid].  

PubMed

Adipic acid is a six-carbon dicarboxylic acid, mainly for the production of polymers such as nylon, chemical fiber and engineering plastics. Its annual demand is close to 3 million tons worldwide. Currently, the industrial production of adipic acid is based on the oxidation of aromatics from non-renewable petroleum resources by chemo-catalytic processes. It is heavily polluted and unsustainable, and the possible alternative method for adipic acid production should be developed. In the past years, with the development of synthetic biology and metabolic engineering, green and clean biotechnological methods for adipic acid production attracted more attention. In this study, the research advances of adipic acid and its precursor production are reviewed, followed by addressing the perspective of the possible new pathways for adipic acid production. PMID:24432653

Han, Li; Chen, Wujiu; Yuan, Fei; Zhang, Yuanyuan; Wang, Qinhong; Ma, Yanhe

2013-10-01

184

Evaluation of disinfection by-products formation during chlorination and chloramination of dissolved natural organic matter fractions isolated from a filtered river water  

Microsoft Academic Search

Dissolved natural organic matter (DOM) in a filtered river water was isolated and fractionated into six different fractions. Trihalomethanes (THMs) and haloacetic acids (HAAs) formed from these isolated DOM fractions during chlorination and chloramination were determined. Results show that the hydrophobic acid, hydrophilic acid, hydrophilic base and hydrophobic neutral are major precursors of THMs and HAAs. There exist good correlations

Jinfeng Lu; Tao Zhang; Jun Ma; Zhonglin Chen

2009-01-01

185

Coagulation of natural organic material: effects on speciation of halogenated disinfection by-products  

Microsoft Academic Search

A recent paper by Liang and Singer showed that haloacetic acid (HAA) precursors were removed by coagulation to a greater degree than trihalomethane (THM) precursors. Furthermore, they showed that coagulation generally removed more trihaloacetic acid precursors than THM precursors but removed dihaloacetic acid precursors and THM precursors to a similar degree. The objectives of this current study were to compare

P. C. Singer; L. Liang

2004-01-01

186

78 FR 20029 - Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance...  

Federal Register 2010, 2011, 2012, 2013, 2014

...AGENCY 40 CFR Part 180 [EPA-HQ-OPP-2013-0057; FRL-9381-2] Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance Exemption AGENCY: Environmental Protection Agency (EPA). ACTION:...

2013-04-03

187

Microorganisms for producing organic acids  

DOEpatents

Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

Pfleger, Brian Frederick; Begemann, Matthew Brett

2014-09-30

188

4, 29012944, 2007 Acid deposition,  

E-print Network

short-term re- ductions in stream acidity, particularly base cation dilution and organic acid increasesHESSD 4, 2901­2944, 2007 Acid deposition, climate change and acid extremes C. D. Evans et al. Title System Sciences Effects of decreasing acid deposition and climate change on acid extremes in an upland

Boyer, Edmond

189

THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE  

EPA Science Inventory

This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

190

Acid Rain Learning Activities  

NSDL National Science Digital Library

These suggestions for activities allow students to learn about acid deposition in new and interactive ways, both in and out of the classroom. The suggestions are for individuals and small groups, the class as a whole, or for field trips. Students may contact local experts about acid rain issues, investigate the energy sources used to generate electricity by their local power companies, collect cartoons about acid rain and air pollution, or play the roles of scientists or interested parties involved in investigations of acid rain issues. Field trip ideas include visiting a local museum or science center to see exhibits or resources on acid rain, and visiting a local cemetary to examine the effects of acid rain on the headstones.

191

Acid rain on Bermuda  

Microsoft Academic Search

Increased acidity of precipitation due to combustion of fossil fuels has been well documented for both the eastern USA1 and Canada2. The SO2 and NOxemitted by the burning of coal, natural gas, fuel oil and petrol are oxidized in the atmosphere to sulphuric and nitric acids which subsequently give rise to acid precipitation1. However, the SO2 and NOx emitted, and

Timothy Jickells; Anthony Knap; Thomas Church; James Galloway; John Miller

1982-01-01

192

Excretion of ascorbic acid  

Microsoft Academic Search

Summary  The literature concerning the excretion of ascorbic acid is reviewed and discussed.\\u000a \\u000a Experiments have been carried out and results are given, to show the extent of the marked hourly variations which occur in\\u000a the excretion of ascorbic acid by the kidneys. This variation is present at all physiological ascorbic acid blood levels and\\u000a is not related to the urine pH

J. Deeny; E. T. Murdock; J. J. Rogan

1944-01-01

193

Lactic Acid Bacteria  

NSDL National Science Digital Library

This on-line exercise is focused on lactic acid bacteria, a group of related bacteria that produce lactic acid as a result of carbohydrate fermentation. It includes a protocol for the enrichment of lactic acid bacteria from enriched samples (like yogurt, sauerkraut, decaying plant matter, and tooth plaque). Three parameters are measured: growth, culture diversity, and pH. The exercise also includes instructions for the isolation of some of these bacteria by using the streak-plate method.

194

Recovery of organic acids  

DOEpatents

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Golden, CO); Eggeman, Timothy J. (Lakewood, CO)

2009-10-13

195

Recovery of organic acids  

DOEpatents

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Menlo Park, CA); Eggeman, Timothy J. (Lakewood, CO)

2011-11-01

196

Acid Rain Students' Site  

NSDL National Science Digital Library

The EPA developed this colorful website to teach students all about acid rain. First, through clear descriptions and helpful figures users can learn the characteristics of acid rain, its dangers, and how to control it. The website offers an interactive connect-the-dots, word searches, crossword puzzles, and other games. A short movie provides an overview of how the use of coal contributes to acid rain and acid rain's impacts on ecosystems and human health. The website also offers an introduction to the pH scale and tools to measure the pH.

197

Molecular Structure of Fumaric acid  

NSDL National Science Digital Library

Fumaric acid is odorless and colorless or white crystalline powder with a fruit acid taste. Fumaric acid is used as a substitute of tartaric acid in beverages and baking powders and as a replacement for citric acid in fruits drinks. It is also used as antioxidant to prevent rancidity in butter, cheese, powdered milk, and other foodstuff. In addition, fumaric acid is a chemical intermediate in the manufacture of pharmaceuticals, synthetic resins and plastics. Fumaric acid can be prepared by catalytic oxidation of benzene or by bacterial action on glucose and it is involved in the production of energy from food. Fumaric acid (known as trans-butanedioic acid) is the trans isomer of maleic acid (also called cis-butanedioic acid). Fumaric acid is more stable than maleic acid and can be prepared by heating maleic acid.

2004-11-05

198

Hydroxybenzoic acids from Boreava orientalis  

Microsoft Academic Search

A new guaiacylglycerol ether, threo-guaiacylglycerol-8?-vanillic acid ether, pyrocatechuic acid, pyrocatechuic acid 3-O-?-d-glucoside, gentisic acid, gentisic acid 5-O-?-d-glucoside, vanillic acid and vanillic acid 4-O-?-d-glucoside were identified from fruits of Boreava orientalis. Structural elucidation was carried out on the basis of UV, mass, 1H and 13C NMR spectral data, including 2D shift-correlation and selective INEPT experiments.

Akiyo Sakushima; Maksut Co?kun; Takashi Maoka

1995-01-01

199

Acid in water  

NSDL National Science Digital Library

Plants and animals that live in water create some amount of acid in the water. The carbon dioxide that plants and animals release into the water makes the water acidic and unsafe for living organisms. This is why the water of captive aquatic animals and plants must be changed often.

Laszlo Ilyes (None; )

2007-05-16

200

EXPOSURES TO ACIDIC AEROSOLS  

EPA Science Inventory

Ambient monitoring of acid aerosol in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. easurements made in Kingston, TN, and Stuebenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 ti...

201

Controlling acid rain  

E-print Network

High concentrations of sulfuric and nitric acid in raTn fn the northeastern USA are caused by the large scale combustion of fossil fuels within this region. Average precipitation acidity is pH 4.2, but spatial and temporal ...

Fay, James A.

1983-01-01

202

EFFECTS OF ACID PRECIPITATION  

EPA Science Inventory

Recent reviews of available data indicate that precipitation in a large region of North America is highly acidic when its pH is compared with the expected pH value of 5.65 for pure rain water in equilibrium with CO2. A growing body of evidence suggests that acid rain is responsib...

203

Toxicology of Perfluoroalkyl Acids*  

EPA Science Inventory

The perfluoroalkyl acids (PFAAs) are a family of organic chemicals consisting of a perfluorinated carbon backbone (4-12 in length) and an acidic functional moiety (carboxylate or sulfonate). These compounds are chemically stable, have excellent surface-tension reducing properties...

204

Toxicology of Perfluoroalkyl acids  

EPA Science Inventory

The Perfluoroalkyl acids(PFAAs) area a family of organic chemicals consisting of a perflurinated carbon backbone (4-12in length) and a acidic functional moiety (Carboxylate or sulfonate). These compounds have excellent surface-tension reducing properties and have numerous industr...

205

Acids in Proteins  

NSDL National Science Digital Library

This lesson describes how amino acids build proteins in a person's body. Amino acids are the chemical building blocks for the structure of an organism. A link to a quiz is provided at the end of the lesson to check comprehension.

2012-06-19

206

Mutant fatty acid desaturase  

DOEpatents

The present invention relates to a method for producing mutants of a fatty acid desaturase having a substantially increased activity towards fatty acid substrates with chains containing fewer than 18 carbons relative to an unmutagenized precursor desaturase having an 18 carbon atom chain length substrate specificity. The method involves inducing one or more mutations in the nucleic acid sequence encoding the precursor desaturase, transforming the mutated sequence into an unsaturated fatty acid auxotroph cell such as MH13 E. coli, culturing the cells in the absence of supplemental unsaturated fatty acids, thereby selecting for recipient cells which have received and which express a mutant fatty acid desaturase with an elevated specificity for fatty acid substrates having chain lengths of less than 18 carbon atoms. A variety of mutants having 16 or fewer carbon atom chain length substrate specificities are produced by this method. Mutant desaturases produced by this method can be introduced via expression vectors into prokaryotic and eukaryotic cells and can also be used in the production of transgenic plants which may be used to produce specific fatty acid products.

Shanklin, John; Cahoon, Edgar B.

2004-02-03

207

Urobilinogen AscorbicAcid  

E-print Network

Date Lot # Bilirubin Urobilinogen Ketone AscorbicAcid Glucose Protein Blood pH Nitrite Leukocytes Specific Gravity hCG: Method Lot # Acetest® (Ketone): Lot # Clinitest® (Glucose): Lot # Ictotest®(Bilirubin AND DATA ENTRY FORMS #12;Date Lot # Bilirubin Urobilinogen Ketone AscorbicAcid Glucose Protein Blood p

Rodriguez, Carlos

208

Omega-3 Fatty Acids  

MedlinePLUS

Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount of triglycerides (a fat-like ... people with very high triglycerides. Omega-3 fatty acids are in a class of medications called antilipemic ...

209

Fats and fatty acids  

Technology Transfer Automated Retrieval System (TEKTRAN)

The absolute fat requirement of the human species is the amount of essential fatty acids needed to maintain optimal fatty acid composition of all tissues and normal eicosanoid synthesis. At most, this requirement is no more than about 5% of an adequate energy intake. However, fat accounts for appro...

210

Amino Acid Crossword Puzzle  

ERIC Educational Resources Information Center

Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

Sims, Paul A.

2011-01-01

211

What Causes Acid Rain?  

NSDL National Science Digital Library

The phenomenon is the formation of acid rain. The resource explains the chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air, mix and react with water and other chemicals to form more acidic pollutants that dissolve very easily in water and can be carried long distances where they become part of rain, sleet, snow, and fog.

212

Acid (and Base) Rainbows  

NSDL National Science Digital Library

Students are introduced to the differences between acids and bases and how to use indicators, such as pH paper and red cabbage juice, to distinguish between them. They learn why it is important for engineers to understand acids and bases.

2014-09-18

213

ACID AEROSOLS ISSUE PAPER  

EPA Science Inventory

The report evaluates scientific information on direct health effects associated with exposure to acid aerosols. The present report is not intended as a complete and detailed review of all literature pertaining to acid aerosols. Rather, an attempt has been made to focus on the eva...

214

Bile acid transporters  

PubMed Central

In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na+ taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OST?-OST?. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers. PMID:19498215

Dawson, Paul A.; Lan, Tian; Rao, Anuradha

2009-01-01

215

Strong Acids (GCMP)  

NSDL National Science Digital Library

Strong Acids: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore the properties of common strong acids. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

216

Acids and Salts (GCMP)  

NSDL National Science Digital Library

Acids and Salts: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore a few properties of common acids and their salts. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

217

Halogenated fatty acids  

Microsoft Academic Search

Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also, chlorinated lipids have been found in meat exposed to hypochlorite disinfected water, and in chlorine-treated flour and in

Peter Sundin

1997-01-01

218

Acid Rain Revisited  

NSDL National Science Digital Library

The results of a long term study of the effects of acidic deposition in the Northeast were published in Bioscience this week, and they suggest that forests, lakes, and streams of the Northeastern US are not recovering from the toxic effects of acid rain despite significant cuts in the power plant emissions of sulfur dioxide and nitrogen oxide -- two major contributors to the problem. "Acid rain," more accurately called acidic deposition, causes toxic forms of aluminum to concentrate in soil and water, vital calcium and magnesium to be leached from trees, and surface waters to become inhospitable to aquatic biota. The study showed that, after 30 years of federally mandated air emission reductions, sulfur dioxide emissions have decreased while nitrogen oxide emissions have remained the same and that acidic deposition-related problems continue to plague New York and New England.

Sanders, Hilary C.

2001-01-01

219

Metabolic fate of oleic acid, palmitic acid and stearic acid in cultured hamster hepatocytes.  

PubMed Central

Unlike other saturated fatty acids, dietary stearic acid does not appear to raise plasma cholesterol. The reason for this remains to be established, although it appears that it must be related to inherent differences in the metabolism of the fatty acid. In the present study, we have looked at the metabolism of palmitic acid and stearic acid, in comparison with oleic acid, by cultured hamster hepatocytes. Stearic acid was taken up more slowly and was poorly incorporated into both cellular and secreted triacylglycerol. Despite this, stearic acid stimulated the synthesis and secretion of triacylglycerol to the same extent as the other fatty acids. Incorporation into cellular phospholipid was lower for oleic acid than for palmitic acid and stearic acid. Desaturation of stearic acid, to monounsaturated fatty acid, was found to be greater than that of palmitic acid. Oleic acid produced from stearic acid was incorporated into both triacylglycerol and phospholipid, representing 13% and 6% respectively of the total after a 4 h incubation. Significant proportions of all of the fatty acids were oxidized, primarily to form ketone bodies, but by 8 h more oleic acid had been oxidized compared with palmitic acid and stearic acid. PMID:8670161

Bruce, J S; Salter, A M

1996-01-01

220

EXPOSURE TO A P13KINASE INHIBITOR PRODUCED DYSMORPHOGENESIS IN NEURULATION-STAGED MOUSE EMBRYOS IN CULTURE  

EPA Science Inventory

The haloacetic acids (HAA) are a family of chemicals that are drinking water disinfection byproducts. We previously reported that bromo- and chloro-acetic acids alter embryonic development when mouse conceptuses are directly exposed to these xenobiotics in whole embryo culture. C...

221

Sulfuric Acid on Europa  

NASA Technical Reports Server (NTRS)

Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

This image is based on data gathered by Galileo's near infrared mapping spectrometer.

Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

1999-01-01

222

Trans Fatty Acids  

NASA Astrophysics Data System (ADS)

Fats and their various fatty acid components seem to be a perennial concern of nutritionists and persons concerned with healthful diets. Advice on the consumption of saturated, polyunsaturated, monounsaturated, and total fat bombards us from magazines and newspapers. One of the newer players in this field is the group of trans fatty acids found predominantly in partially hydrogenated fats such as margarines and cooking fats. The controversy concerning dietary trans fatty acids was recently addressed in an American Heart Association (AHA) science advisory (1) and in a position paper from the American Society of Clinical Nutrition/American Institute of Nutrition (ASCN/AIN) (2). Both reports emphasize that the best preventive strategy for reducing risk for cardiovascular disease and some types of cancer is a reduction in total and saturated fats in the diet, but a reduction in the intake of trans fatty acids was also recommended. Although the actual health effects of trans fatty acids remain uncertain, experimental evidence indicates that consumption of trans fatty acids adversely affects serum lipid levels. Since elevated levels of serum cholesterol and triacylglycerols are associated with increased risk of cardiovascular disease, it follows that intake of trans fatty acids should be minimized.

Doyle, Ellin

1997-09-01

223

Folic Acid: Data and Statistics  

MedlinePLUS

... pregnancy. [ Read article ] Use of Supplements Containing Folic Acid Among Women of Childbearing Age -- United States 2007 ... women of childbearing age: 40% reported taking folic acid daily. 81% reported awareness of folic acid. 12% ...

224

Fatty Acid Carcass Mapping  

E-print Network

positively correlated with the MUFA:SFA ratio. Also, the perception of beef can be influenced by the oleic acid concentration. Because fatty acids have very different melting points, variation in their composition has an important effect on firmness... or softness of the fat in meat, especially the s.c. and i.m. fats (Wood et al., 2003). This can also alter shelf-life depending on the double bonds of the unsaturated fatty acids, whether or not they will oxidize rapidly and become rancid and discolored...

Turk, Stacey N.

2010-01-14

225

Strongly Acidic Auxin Indole-3-Methanesulfonic Acid  

PubMed Central

A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles. PMID:16664007

Cohen, Jerry D.; Baldi, Bruce G.; Bialek, Krystyna

1985-01-01

226

Molecular Structure of Gallic acid  

NSDL National Science Digital Library

Gallic acid is found in its free state and combined with the tannin molecule, from which it can be extracted by the hydrolysis of tannic acid with sulfuric acid. Since one molecule of gallic acid has a carboxylic acid group and hydroxyl groups, it can react with another molecule of gallic acid to form an ester, digallic acid. When heated above 200 degrees C, gallic acid loses carbon dioxide to form pyrogallol (1,2,3-trihydroxybenzene, C6H3(OH)3), which is used in the production of azo dyes, photographic developers, and in laboratories for absorbing oxygen.

2003-05-08

227

Acid-Base Tutorial  

NSDL National Science Digital Library

Website for anyone wanting to become more familiar with the physiology of acid-base balance in clinical medicine. Several pages are interactive. Numerical results are accompanied by text interpretations to facilitate recognition and understanding.

MD Alan W. Grogono (Tulane University School of Medicine Dept. of Anesthesiology)

2002-06-01

228

(Acid rain workshop)  

SciTech Connect

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment Program, the United Nations Economic and Social Commission for Asia and the Pacific, and the World Bank. Papers presented on the first day discussed how the experience gained with acid rain in North America and Europe might be applied to the Asian situation. Papers describing energy use projections, sulfur emissions, and effects of acid rain in several Asian countries were presented on the second day. The remaining time was allotted to discussion, planning, and writing plans for a future research program.

Turner, R.S.

1990-12-05

229

Difficult Decisions: Acid Rain.  

ERIC Educational Resources Information Center

Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

Miller, John A.; Slesnick, Irwin L.

1989-01-01

230

ACID RAIN CONTROL OPTIONS  

EPA Science Inventory

The paper discusses acid rain control options available to the electric utility industry. They include coal switching, flue gas desulfurization, and such emerging lower cost technologies as Limestone Injection Multistage Burners (LIMB) and Advanced Silicate (ADVACATE) both develo...

231

Acid Violence in Pakistan  

E-print Network

Pakistan by the Asian Human Rights Commission. 97 Anwary, Acid Violence and Medical Care; Sexual assaults and rapespakistan-urban-women-get-beaten- by-their-husbands_1663675 Abid, Zehra. “Journalistic ethics: How the media traumatises rape

Zia, Taiba

2013-01-01

232

Polymers for acid thickening  

SciTech Connect

Acids, thickened with branched emulsion or suspension polymers of diallyldimethylammonium chloride are useful as oil well drilling and fracturing fluids for stimulating well production and in other applications, such as thickeners for cosmetics, paints, adhesives, textiles and printing inks.

Dixon, K.W.

1980-09-30

233

Amino Acids and Chirality  

NASA Technical Reports Server (NTRS)

Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

Cook, Jamie E.

2012-01-01

234

Boric Acid Poisoning  

PubMed Central

Boric acid poisoning in 11 infants, occurring in the newborn nursery as a result of the accidental and inadvertent use of 2.5% boric acid in the preparation of the formulae, is reported. Five of the infants died. All except two exhibited the classical symptomatology of acute boric acid poisoning, namely, diarrhea, vomiting, erythema, exfoliation, desquamation of the skin, and marked central nervous system irritation. Early manifestations of poisoning were nonspecific, and one patient died before skin manifestations were noted. Peritoneal dialysis, instituted in nine cases, was found to be the most effective method of treatment. It is recommended that boric acid, which is of doubtful therapeutic value, should be completely removed from hospitals, dispensaries and pharmacopoeias. ImagesFig. 1Fig. 2 PMID:14166459

Wong, L. C.; Heimbach, M. D.; Truscott, D. R.; Duncan, B. D.

1964-01-01

235

Amoxicillin and Clavulanic Acid  

MedlinePLUS

... is used to treat certain infections caused by bacteria, including infections of the ears, lungs, sinus, skin, ... antibiotics. It works by stopping the growth of bacteria. Clavulanic acid is in a class of medications ...

236

Acid-base chemistry  

SciTech Connect

The book is not a research compendium and there are no references to the literature. It is a teaching text covering the entire range of undergraduate subject matter dealing with acid-base chemistry (some of it remotely) as taught in inorganic, analytical, and organic chemistry courses. The excellent chapters VII through IX deal in detail with the quantitative aspects of aqueous acid-base equilibria (salt hydrolysis and buffer, titrations, polyprotic and amphoteric substances).

Hand, C.W.; Blewit, H.L.

1985-01-01

237

Acid Rain Lesson Plan  

NSDL National Science Digital Library

Five articulated lessons focus on air quality using classroom and field data collection activities. Case study in Great Smoky Mountains has broader application. Background and data for lessons on: the pH scale, understanding acid vs. base, collecting data, mapping relationship of weather events to acid rain. Links to NPS data on air quality, current values, atlas and reports, packaged datasets on ozone, meteorological conditions and other parameters. Also available: teacher resources; educator workshops.

238

Domoic Acid Fact Sheet  

NSDL National Science Digital Library

This online fact sheet illustrates the transfer of domoic acid through the food web. Domoic acid is a nerve toxin produced by a naturally occurring Harmful Algal Bloom (HAB) usually (but not always) of the genus Pseudonitzchia. The sheet explains what to do if you find a sick or dead animal and includes contact information for injured/sick/entangled animal rescue networks in California.

Channel Islands National Marine Sanctuary

239

Omega3 Fatty Acids  

Microsoft Academic Search

The research conducted in avians with emphasis on omega (?)-3 fatty acid enrichment of edible meat portions and the use of\\u000a fertilized eggs as a unique model for nutrition research is addressed. In a typical Western diet, over 70% of dietary fat\\u000a is supplied through animal products. Considering the health benefits of ?-3 fatty acids, feeding strategies have been adopted

Gita Cherian

240

Managing bile acid diarrhoea.  

PubMed

Bowel symptoms including diarrhoea can be produced when excess bile acids (BA) are present in the colon. This condition, known as bile acid or bile salt malabsorption, has been under recognized, as the best diagnostic method, the (75)Se-homocholic acid taurine (SeHCAT) test, is not available in many countries and is not fully utilized in others. Reduced SeHCAT retention establishes that this is a complication of many other gastrointestinal diseases. Repeated studies show SeHCAT tests are abnormal in about 30% of patients otherwise diagnosed as diarrhoea-predominant irritable bowel syndrome or functional diarrhoea, with an estimated population prevalence of around 1%. Recent work suggests that the condition previously called idiopathic bile acid malabsorption (BAM) is not in fact due to a defect in absorption, but results from an overproduction of BA because of defective feedback inhibition of hepatic bile acid synthesis, a function of the ileal hormone fibroblast growth factor 19 (FGF19). The approach to treatment currently depends on binding excess BA, to reduce their secretory actions, using colestyramine, colestipol and, most recently, colesevelam. Colesevelam has a number of potential advantages that merit further investigation in trials directed at patients with bile acid diarrhoea. PMID:21180614

Walters, Julian R F; Pattni, Sanjeev S

2010-11-01

241

Managing bile acid diarrhoea  

PubMed Central

Bowel symptoms including diarrhoea can be produced when excess bile acids (BA) are present in the colon. This condition, known as bile acid or bile salt malabsorption, has been under recognized, as the best diagnostic method, the 75Se-homocholic acid taurine (SeHCAT) test, is not available in many countries and is not fully utilized in others. Reduced SeHCAT retention establishes that this is a complication of many other gastrointestinal diseases. Repeated studies show SeHCAT tests are abnormal in about 30% of patients otherwise diagnosed as diarrhoea-predominant irritable bowel syndrome or functional diarrhoea, with an estimated population prevalence of around 1%. Recent work suggests that the condition previously called idiopathic bile acid malabsorption (BAM) is not in fact due to a defect in absorption, but results from an overproduction of BA because of defective feedback inhibition of hepatic bile acid synthesis, a function of the ileal hormone fibroblast growth factor 19 (FGF19). The approach to treatment currently depends on binding excess BA, to reduce their secretory actions, using colestyramine, colestipol and, most recently, colesevelam. Colesevelam has a number of potential advantages that merit further investigation in trials directed at patients with bile acid diarrhoea. PMID:21180614

Walters, Julian R. F.; Pattni, Sanjeev S.

2010-01-01

242

Acid Rain, pH & Acidity: A Common Misinterpretation.  

ERIC Educational Resources Information Center

Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

Clark, David B.; Thompson, Ronald E.

1989-01-01

243

Original article Acid stress susceptibility and acid adaptation  

E-print Network

microor- ganisms. Fermentation of lactose by lactic acid bacteria in dairy products, in particular, leads to the accumulation of the end-product lactic acid. Furthermore, bacteria provided in fermented food are exposedOriginal article Acid stress susceptibility and acid adaptation of Propionibacterium freudenreichii

Paris-Sud XI, Université de

244

CONVERSION OF OLEIC ACID TO BRANCHED-CHAIN FATTY ACIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Oleic acid and linoleic acid are the most abundant fatty acids of cottonseed oil. As part of a project to develop new value-added industrial applications for cottonseed oil (such as biodiesel, fuel additives, and lubricants), studies were conducted in the synthetic conversion of oleic acid to branc...

245

What is Acid Rain? Explore the Acid Lake  

NSDL National Science Digital Library

Acid rain is a type of air pollution that occurs when certain chemicals mix with water in the air. Most chemicals that cause acid rain come from the emissions from factories and cars. Acid rain looks just like 'normal' rain but when it falls, it can hurt plants and animals. For example, when acid rain falls into a lake or river, it makes that body of water more acidic. Many plants and animals cannot live in acidic water. Play this game, from Earth Day Canada's EcoKids program, to learn more about acid rain and its impact on the environment.

Earth Day Canada

2010-01-01

246

DOCOSAHEXAENOIC ACID AND ARACHIDONIC ACID PREVENT ESSENTIAL FATTY ACID DEFICIENCY AND HEPATIC STEATOSIS  

PubMed Central

Objectives Essential fatty acids are important for growth, development, and physiologic function. Alpha-linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, we hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids. Methods Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, we provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis. Results Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks. Conclusion Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without alpha-linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model. PMID:22038210

Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Fallon, Erica M.; Gura, Kathleen M.; Nose, Vania; Bistrian, Bruce R.; Puder, Mark

2012-01-01

247

Atmospheric Dust and Acid Rain  

Microsoft Academic Search

Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid

Lars O. Hedin; Gene E. Likens

1996-01-01

248

Malvalic Acid and its Structure  

Microsoft Academic Search

SOME of the properties of a biologically active C18 fatty acid isolated from Malva verticillata and M. parviflora have been reported1. The name `malvalic' acid is now proposed for this acid, which was previously referred to as ``Halphen acid'' because it gave rise to the Halphen colour test.

J. J. Macfarlane; F. S. Shenstone; J. R. Vickery

1957-01-01

249

Molecular Structure of Malonic acid  

NSDL National Science Digital Library

Propanedioic acid is a dibasic carboxylic acid that was first synthesized by oxidizing malic acid in 1858 by a scientist named Dessaigne. Naturally, propandioic acid is found in apples. This chemical is relatively unstable and has few uses, but its ester derivative, diethyl malonate, is used to synthesize useful compounds such as barbiturates, flavors, fragrances, and vitamins (B1 and B6).

2002-10-10

250

Pelargonic acid weed control parameters  

Technology Transfer Automated Retrieval System (TEKTRAN)

Producers and researchers are interested in pelargonic acid (nonanoic acid) as a broad-spectrum post-emergence or burn-down herbicide. Pelargonic acid is a fatty acid naturally occurring in many plants and animals, and present in many foods we consume. The objective of this research was to determine...

251

Ursodeoxycholic acid, 7-ketolithocholic acid, and chenodeoxycholic acid are primary bile acids of the nutria (Myocastor coypus).  

PubMed

Because ursodeoxycholic and chenodeoxycholic acids are interconverted in humans via 7-ketolithocholic acid, bile acid metabolism was studied in the nutria (Myocastor coypus), the bile of which is known to contain these three bile acids. Relative concentrations of ursodeoxycholic (37% +/- 20%), 7-ketolithocholic (33% +/- 17%), and chenodeoxycholic (17% +/- 9%) acids in gallbladder bile were unchanged by 5-20 h of complete biliary diversion (n = 7). Injection of either [14C]cholesterol, [14C]ursodeoxycholic, [14C]7-ketolithocholic acid, or a mixture of [7 beta-3H]chenodeoxycholic acid and [14C]chenodeoxycholic acid into bile fistula nutria demonstrated that all three bile acids can be synthesized hepatically from cholesterol, that they are interconverted sparingly (2%-5%) by the liver, but that 7-ketolithocholic acid is an intermediate in the hepatic transformation of chenodeoxycholic acid to ursodeoxycholic acid. An animal that had been fed antibiotics showed an unusually elevated concentration of ursodeoxycholic acid in gallbladder and hepatic bile, suggesting that bacterial transformation of ursodeoxycholic acid in the intestine may be a source of some biliary chenodeoxycholic acid and 7-ketolithocholic acid. PMID:3943698

Tint, G S; Bullock, J; Batta, A K; Shefer, S; Salen, G

1986-03-01

252

Molecular Structure of Succinic acid  

NSDL National Science Digital Library

Succinic acid is an odorless and colorless crystal, triclinic or monoclinic prism with a very acid taste. Succinic acid is one of the natural acids found in broccoli, rhubarb, beets, asparagus, fresh meat extracts, sauerkraut and cheese. It is also a constituent of almost all plant and animal tissues and plays an important role in intermediary metabolism. Succinic acid is produced commercially by catalytic hydrogenation of maleic or fumaric acid or by acid hydrolysis of succinonitrile. Succinic acid is used in flavoring for food and beverages, and in the manufacture of lacquers, dyes, esters for perfumes, succinates, in photography and in foods as a sequestrant, buffer and neutralizing agent. Succinic acid has uses in certain drug compounds and in agricultural production. An interesting fact, succcinic acid has also been found in meteorites.

2004-11-11

253

Domoic acid epileptic disease.  

PubMed

Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis. PMID:24663110

Ramsdell, John S; Gulland, Frances M

2014-03-01

254

Analysis of Bile Acids  

NASA Astrophysics Data System (ADS)

Bile acids constitute a large family of steroids in vertebrates, normally formed from cholesterol and carrying a carboxyl group in a side-chain of variable length. Bile alcohols, also formed from cholesterol, have similar structures as bile acids, except for the absence of a carboxyl group in the steroid skeleton. The conversion of cholesterol to bile acids and/or bile alcohols is of major importance for maintenance of cholesterol homeostasis, both from quantitative and regulatory points of view (Chiang, 2004; Kalaany and Mangelsdorf, 2006; Moore, Kato, Xie, et al., 2006; Scotti, Gilardi, Godio, et al., 2007). Appropriately conjugated bile acids and bile alcohols (also referred to as bile salts) are secreted in bile and serve vital functions in the absorption of lipids and lipid-soluble compounds (Hofmann, 2007). Reliable analytical methods are required for studies of the functions and pathophysiological importance of the variety of bile acids and bile alcohols present in living organisms. When combined with genetic and proteomic studies, analysis of these small molecules (in today's terminology: metabolomics, steroidomics, sterolomics, cholanoidomics, etc.) will lead to a deeper understanding of the integrated metabolic processes in lipid metabolism.

Sjövall, Jan; Griffiths, William J.; Setchell, Kenneth D. R.; Mano, Nariyasu; Goto, Junichi

255

Optical high acidity sensor  

DOEpatents

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and, a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber.

Jorgensen, Betty S. (Jemez Springs, NM); Nekimken, Howard L. (Los Alamos, NM); Carey, W. Patrick (Lynnwood, WA); O'Rourke, Patrick E. (Martinez, GA)

1997-01-01

256

Optical high acidity sensor  

DOEpatents

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber. 10 figs.

Jorgensen, B.S.; Nekimken, H.L.; Carey, W.P.; O`Rourke, P.E.

1997-07-22

257

Science Shorts: Understanding Acid Rain  

NSDL National Science Digital Library

You may have heard acid rain mentioned as an environmental problem. It doesn't mean that a strong chemical is raining from the sky. The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. However, a small change in how acidic precipitation is can have a profound effect. This month's activity will help students understand the effect of acid rain on buildings and statues.

Kathleen Damonte

2004-11-01

258

Acid rain degradation of nylon  

Microsoft Academic Search

Acid rain, precipitation with a pH less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid

Kyllo

1984-01-01

259

Molecular Structure of Citric Acid  

NSDL National Science Digital Library

Citric Acid was first isolated in 1734 by Carl Wilhelm Scheele. Citric acid is found in many fruits, in particular lemons, grapefruit, and oranges. Several types of bacteria and fungi are also known to produce citric acid. In fact, the fungus Aspergillus niger produces the vast majority of citric acid, which is used in almost all carbonated sodas. Additionally, citric acid is also used to clean stainless steel.

2002-08-13

260

49 CFR 173.158 - Nitric acid.  

Code of Federal Regulations, 2013 CFR

...with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as impurities...greater concentration which does not contain sulfuric acid or hydrochloric acid as...

2013-10-01

261

49 CFR 173.158 - Nitric acid.  

Code of Federal Regulations, 2011 CFR

...with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as impurities...greater concentration which does not contain sulfuric acid or hydrochloric acid as...

2011-10-01

262

49 CFR 173.158 - Nitric acid.  

Code of Federal Regulations, 2014 CFR

...with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as impurities...greater concentration which does not contain sulfuric acid or hydrochloric acid as...

2014-10-01

263

49 CFR 173.158 - Nitric acid.  

Code of Federal Regulations, 2012 CFR

...with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as impurities...greater concentration which does not contain sulfuric acid or hydrochloric acid as...

2012-10-01

264

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid  

SciTech Connect

An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

Arceo, Elena; Ellman, Jonathan; Bergman, Robert

2010-05-03

265

Acid neutralizing capacity, alkalinity, and acid-base status of natural waters containing organic acids  

Microsoft Academic Search

The terms acid neutralizing capacity (ANC) and alkalinity (Alk) are extensively employed in the characterization of natural waters, including soft circumneutral or acidic waters. However, in the presence of organic acids, ANC measurements are inconsistent with many conceptual definitions of ANC or Alk and do not provide an adequate characterization of the acid-base chemistry of water. Knowledge of Gran ANC

Harold F. Hemond

1990-01-01

266

The Acid-Base Titration of a Very Weak Acid: Boric Acid  

ERIC Educational Resources Information Center

A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

2012-01-01

267

Sequential injection redox or acid–base titration for determination of ascorbic acid or acetic acid  

Microsoft Academic Search

Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to

Narong Lenghor; Jaroon Jakmunee; Michael Vilen; Rolf Sara; Gary D Christian; Kate Grudpan

2002-01-01

268

Acid rain in Asia  

NASA Astrophysics Data System (ADS)

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

Bhatti, Neeloo; Streets, David G.; Foell, Wesley K.

1992-07-01

269

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2011 CFR

...acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 ...acid amine condensate, polycarboxylic acid salts. (a) Chemical substance and significant...acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject...

2011-07-01

270

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2012 CFR

...acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 ...acid amine condensate, polycarboxylic acid salts. (a) Chemical substance and significant...acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject...

2012-07-01

271

Enantiomeric separation of amino acids and nonprotein amino acids using a particle-loaded  

E-print Network

Enantiomeric separation of amino acids and nonprotein amino acids using a particle acids and three nonprotein amino acids are derivatized with the fluorogenic reagent 4-fluoro-7-nitro-2 liquid chromatography (HPLC). Keywords: Amino acid / Nonprotein amino acid / Capillary

Zare, Richard N.

272

[Studies on interaction of acid-treated nanotube titanic acid and amino acids].  

PubMed

Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination. PMID:20649031

Zhang, Huqin; Chen, Xuemei; Jin, Zhensheng; Liao, Guangxi; Wu, Xiaoming; Du, Jianqiang; Cao, Xiang

2010-06-01

273

Ethylenediaminetetraacetic acid in endodontics  

PubMed Central

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented. PMID:24966721

Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

2013-01-01

274

Acid Deposition Lab  

NSDL National Science Digital Library

In this activity students will design an apparatus and carry out tests of fossil fuels to determine their impact on acid deposition by placing a small amount of a fossil fuel on a cotton puff and burning it to measure if acidic compounds are given off. Students will provide a diagram of their collection device and describe how it should function. Students will then draw a map showing the location of their precipitation collector and develop a graph or chart based on the results they have collected.

275

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite  

NASA Astrophysics Data System (ADS)

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

1992-11-01

276

Lactic acid bacterial cell factories for gamma-aminobutyric acid  

Microsoft Academic Search

Gamma-aminobutyric acid is a non-protein amino acid that is widely present in organisms. Several important physiological functions\\u000a of gamma-aminobutyric acid have been characterized, such as neurotransmission, induction of hypotension, diuretic effects,\\u000a and tranquilizer effects. Many microorganisms can produce gamma-aminobutyric acid including bacteria, fungi and yeasts. Among\\u000a them, gamma-aminobutyric acid-producing lactic acid bacteria have been a focus of research in recent

Haixing Li; Yusheng Cao

2010-01-01

277

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite  

NASA Technical Reports Server (NTRS)

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

1992-01-01

278

Synthesis of acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters  

DOEpatents

A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a solvent selected from the group consisting of water, ethyl acetate, chloroform, acetone, ethanol, tetrahydrofuran and acetonitrile, to form a quaternary ammonium salt of the lower alkyl 5-bromolevulinate; and b) hydrolyzing the quaternary ammonium salt with an inorganic acid to form an acid addition salt of delta-aminolevulinic acid.

Moens, Luc (Lakewood, CO)

2003-06-24

279

Molecular Structure of Aspartic Acid  

NSDL National Science Digital Library

Aspartate was first isolated in 1868 from legumin in plant seeds. Aspartic acid forms colorless crystals that are soluble in water and insoluble in alcohols and ethers. This is a naturally occurring nonessential amino acid that is produced in the liver from oxaloacetic acid, but is plentiful in meats and sprouting seeds. The amino acid is important in the Krebs cycle as well as the urea cycle, where it is vital in the elimination of dietary waste products. Aspartic acid is required for stamina, brain and neural health. This acid has been found to be important in the functioning of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and in the production of immunoglobin and antibody synthesis. A deficiency of aspartate will lead to fatigue and depression. Aspartic acid has many uses that include biological and clinical studies, preparation of culture media, and it also functions as a detergent, fungicide, germicide, and metal complexation.

2002-08-20

280

Specific bile acids inhibit hepatic fatty acid uptake  

PubMed Central

Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. Here we tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. In summary, the data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease. PMID:22531947

Nie, Biao; Park, Hyo Min; Kazantzis, Melissa; Lin, Min; Henkin, Amy; Ng, Stephanie; Song, Sujin; Chen, Yuli; Tran, Heather; Lai, Robin; Her, Chris; Maher, Jacquelyn J.; Forman, Barry M.; Stahl, Andreas

2012-01-01

281

Acid Mine Drainage Remediation  

NSDL National Science Digital Library

In this video, an environmental technologist visits an abandoned coal mine in Kentucky to talk about how a remediation system (a series of settling ponds and treatment cells) is neutralizing the acid drainage flowing from the mine and keeping it from damaging a creek downstream.

2010-12-10

282

The Acid Rain Debate.  

ERIC Educational Resources Information Center

Describes an activity which provides opportunities for role-playing as industrialists, ecologists, and government officials. The activity involves forming an international commission on acid rain, taking testimony, and, based on the testimony, making recommendations to governments on specific ways to solve the problem. Includes suggestions for…

Bybee, Rodger; And Others

1984-01-01

283

Federal Acid Rain Games  

Microsoft Academic Search

Federal environmental policy, designed to control acid rain, is shaped after the hierarchy of the system, and is controlled simultaneously by regional and central governments. Each governmental level controls one of two policy instruments: pollution abatement production and pollution tax. In a two-stage game where regional governments are Stackelberg leaders and control pollution taxes, the subgame perfect equilibrium is socially

Arthur J. Caplan; Emilson C. D. Silva

1999-01-01

284

The Acid Rain Game.  

ERIC Educational Resources Information Center

Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

Rakow, Steven J.; Glenn, Allen

1982-01-01

285

Acid Rain Classroom Projects.  

ERIC Educational Resources Information Center

Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

Demchik, Michael J.

2000-01-01

286

The Acid Rain Debate.  

ERIC Educational Resources Information Center

Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

Oates-Bockenstedt, Catherine

1997-01-01

287

Acid Rain Investigations.  

ERIC Educational Resources Information Center

Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

Hugo, John C.

1992-01-01

288

Acid rain bibliography  

SciTech Connect

This bibliography identifies 900 citations on various aspects of Acid Rain, covering published bibliographies, books, reports, conference and symposium proceedings, audio visual materials, pamphlets and newsletters. It includes five sections: citations index (complete record of author, title, source, order number); KWIC index; title index; author index; and source index. 900 references.

Sayers, C.S.

1983-09-01

289

Effects of Acid Rain  

NSDL National Science Digital Library

This portal provides links to information on the potential damage caused to the environment by acid rain. An introductory paragraph briefly describes the damage to lakes and streams, building materials, and monuments. Each link access additional information on these topics: surface waters and aquatic animals, forests, automotive coatings, soluble building materials such as marble or limestone, atmospheric haze, and human health effects.

290

Basically Acidic Ink  

NSDL National Science Digital Library

Students hypothesize whether vinegar and ammonia-based glass cleaner are acids or bases. They create designs on index cards using these substances as invisible inks. After the index cards have dried, they apply red cabbage juice as an indicator to reveal the designs.

2014-09-18

291

Acid rain abatement  

Microsoft Academic Search

This patent describes a method of obtaining acid rain abatement from a flue gas containing nitrogen oxides (NOX) and sulfur oxides (SOX). It comprises the steps of treating the flue gas with a reducing agent to remove the remaining oxygen and produce an effluent, the reducing agent being selected from group consisting of natural gas, methane, a mixture of CO

1991-01-01

292

Docosahexaenoic acid and lactation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Docosahexaenoic acid (DHA) is an important component of membrane phospholipids in the retina, and brain, and accumulates rapidly in these tissues during early infancy. DHA is present in human milk, but the amount varies considerably and is largely dependent on maternal diet. This article reviews dat...

293

ACID AEROSOL MEASUREMENT WORKSHOP  

EPA Science Inventory

This report documents the discussion and results of the U.S. EPA Acid Aerosol Measurement Workshop, conducted February 1-3, 1989, in Research Triangle Park, North Carolina. t was held in response to recommendations by the Clean Air Scientific Advisory Committee (CASAC) regarding ...

294

Brain amino acid sensing.  

PubMed

The 20 different amino acids, in blood as well as in the brain, are strictly maintained at the same levels throughout the day, regardless of food intake. Gastric vagal afferents only respond to free glutamate and sugars, providing recognition of food intake and initiating digestion. Metabolic control of amino acid homeostasis and diet-induced thermogenesis is triggered by this glutamate signalling in the stomach through the gut-brain axis. Rats chronically fed high-sugar and high-fat diets do not develop obesity when a 1% (w/v) monosodium glutamate (MSG) solution is available in a choice paradigm. Deficiency of the essential amino acid lysine (Lys) induced a plasticity in rats in response to Lys. This result shows how the body is able to identify deficient nutrients to maintain homeostasis. This plastic effect is induced by activin A activity in the brain, particularly in certain neurons in the lateral hypothalamic area (LHA) which is the centre for amino acid homeostasis and appetite. These neurons respond to glutamate signalling in the oral cavity by which umami taste is perceived. They play a quantitative role in regulating ingestion of deficient nutrients, thereby leading to a healthier life. After recovery from malnutrition, rats prefer MSG solutions, which serve as biomarkers for protein nutrition. PMID:25200295

Tsurugizawa, T; Uneyama, H; Torii, K

2014-09-01

295

Spermatotoxicity of dichloroacetic acid  

EPA Science Inventory

The testicular toxicity of dichloroacetic acid (DCA), a disinfection byproduct of drinking water, was evaluated in adult male rats given both single and multiple (up to 14 d) oral doses. Delayed spermiation and altered resorption of residual bodies were observed in rats given sin...

296

Synthesis of (+)-Coronafacic Acid  

PubMed Central

An enantioselective synthesis of (+)-coronafacic acid has been achieved. Rhodium catalyzed cyclization of an ?-diazoester provided the intermediate cyclopentanone in high enantiomeric purity. Subsequent Fe-mediated cyclocarbonylation of a derived alkenyl cyclopropane gave a bicyclic enone, that then was hydrogenated and carried on to the natural product. PMID:19231870

Taber, Douglass F.; Sheth, Ritesh B.; Tian, Weiwei

2009-01-01

297

Plant fatty acid hydroxylase  

SciTech Connect

The present invention relates to the identification of nucleic acid sequences and constructs, and methods related to the use of these sequences and constructs to produce genetically modified plants for the purpose of altering the composition of plant oils, waxes and related compounds.

Somerville, C.; Loo, F. van de

2000-02-22

298

Plant fatty acid hydroxylase  

DOEpatents

The present invention relates to the identification of nucleic acid sequences and constructs, and methods related thereto, and the use of these sequences and constructs to produce genetically modified plants for the purpose of altering the composition of plant oils, waxes and related compounds.

Somerville, Chris (Portola Valley, CA); van de Loo, Frank (Lexington, KY)

2000-01-01

299

Fatty acid-producing hosts  

DOEpatents

Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

Pfleger, Brian F; Lennen, Rebecca M

2013-12-31

300

Acidizing of Sandstone Reservoirs Using HF and Organic Acids  

E-print Network

Mud acid, which is composed of HCl and HF, is commonly used to remove the formation damage in sandstone reservoirs. However, many problems are associated with HCl, especially at high temperatures. Formic-HF acids have served as an alternative...

Yang, Fei

2012-10-19

301

Sonochemical Esterification of Carboxylic Acids in Presence of Sulphuric Acid  

Microsoft Academic Search

A mild and convenient method for the sonochemical esterif ication of aliphatic, aroma tic, ?,?-unsaturated, mono-and di-carboxylic acids in presence of catalytic amounts of sulphuric acid has been reported.

Jitender M. Khurana; Prabhat K. Sahoo; Golak C. Maikap

1990-01-01

302

Recovery of Carboxylic Acids from Fermentation Broth via Acid Springing  

E-print Network

RECOVERY OF CARBOXYLIC ACIDS FROM FERMENTATION BROTH VIA ACID SPRINGING A Thesis by JIPENG DONG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 2008 Major Subject: Chemical Engineering RECOVERY OF CARBOXYLIC ACIDS FROM FERMENTATION BROTH VIA ACID SPRINGING A Thesis by JIPENG DONG Submitted to the Office of Graduate Studies of Texas A...

Dong, Jipeng

2010-01-14

303

Fatty acid selectivity of lipases: ?-linolenic acid from borage oil  

Microsoft Academic Search

The ?-linolenic acid (Z,Z,Z-6,9,12-octadecatrienoic acid, GLA) present in borage oil free fatty acids was concentrated in esterification reactions that\\u000a were catalyzed by several preparations of the acyl-specific lipase ofGeotrichum candidum. In this manner, a 95% recovery of the GLA originally present in borage oil (25% GLA) was obtained as a highly enriched fatty\\u000a acid fraction with a GLA content of

Thomas A. Foglia; Philip E. Sonnet

1995-01-01

304

Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells  

PubMed Central

Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase) has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-?-boswellic acids (AKBA), a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health. PMID:19951413

2009-01-01

305

Bile acids. LXVII. The major bile acids of Varanus monitor.  

PubMed

The major bile acids of gall bladder bile of Varanus monitor have been separated by thin-layer chromatography and shown to be derivatives of taurine. After alkaline hydrolysis, the free acids were separated by thin-layer and partition chromatography. Identification or characterization of the free acids was facilitated by gas-liquid chromatography and gas-liquid chromatography-mass spectometry of the methyl esters or methyl ester-trimethylsilyl ethers. About 13% of the total bile acids was represented by the C24 acids cholic, deoxycholic, allocholic, chenodeoxycholic, and 12-oxo-3 alpha-hydroxy-5 beta-cholanic acids, of which cholic acid constituted about 50%. The remainder of the bile acids consisted of eight C27 acids of which varanic acid was the major constituent; an isomer of varanic acid and 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestanoic acid were also identified. By chromatographic behavior and mass spectral fragmentation, the structures of four C27 acids with unsaturated side chains were elucidated as follows: 3 alpha, 7 alpha-dihydroxy-5 beta-cholest-23-enoic, 3 alpha, 7 alpha-dihydroxy-5 beta-cholest-24-enoic, 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholest-23-enoic, and 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholest-24-enoic acids. Similarly, the structure of the 12-deoxy analog of varanic acid, 3 alpha, 7 alpha, 24 xi-trihydroxy-5 beta-cholestanoic acid, was suggested for the component that constituted 7% of the total. PMID:7142816

Ali, S S; Stephenson, E; Elliott, W H

1982-09-01

306

Transformation of some hydroxy amino acids to other amino acids  

Microsoft Academic Search

It has been observed that ß-hydroxy-a-amino acids are transformed into other amino acids, when heated in dilute solutions with phosphorous acid, phosphoric acid or their ammonium salts. It has been shown that as in the case of previously reported glycine-aldehyde reactions, glycine also reacts with acetone to give ß-hydroxyvaline under prebiologically feasible conditions. It is suggested, therefore, that the formation

A. S. U. Choughuley; A. S. Subbaraman; Z. A. Kazi; M. S. Chadha

1975-01-01

307

Transformation of some hydroxy amino acids to other amino acids  

Microsoft Academic Search

It has been observed that beta-hydroxy-alpha-amino acids are transformed into other amino acids, when heated in dilute solutions with phosphorous acid, phosphoric acid or their ammonium salts. It has been shown that as in the case of previously reported glycine-aldehyde reactions, glycine also reacts with acetone to give beta-hydroxyvaline under prebiologically feasible conditions. It is suggested, therefore, that the formation

A. S. U. Choughuley; A. S. Subbaraman; Z. A. Kazi; M. S. Chadha

1975-01-01

308

Thiobarbituric Acid Spray Reagent for Deoxy Sugars and Sialic Acids  

Microsoft Academic Search

RECENTLY, new sensitive assays have been reported for deoxy sugars1, 2-keto,3-deoxy sugar acids2-4, and sialic acids5,6. In these assays, the products of periodate oxidation, malonaldehyde from deoxy sugars and beta-formylpyruvic acid from the latter two groups of compounds, are coupled with 2-thiobarbituric acid to produce a bright red chromophore. I wish to report an adaptation of these methods for spraying

Leonard Warren

1960-01-01

309

Boric/sulfuric acid anodize - Alternative to chromic acid anodize  

NASA Astrophysics Data System (ADS)

The suitability of boric acid/sulfuric acid anodizing (BSAA) solution as a more environmentally acceptable replacement of the chromic acid anodizing (CAA) solution was investigated. Results include data on the BSAA process optimization, the corrosion protection performance, and the compatibility with aircraft finishing. It is shown that the BSSA implementation as a substitude for CAA was successful.

Koop, Rodney; Moji, Yukimori

1992-04-01

310

Circulating folic acid in plasma: relation to folic acid fortification  

Technology Transfer Automated Retrieval System (TEKTRAN)

The implementation of folic acid fortification in the United States has resulted in unprecedented amounts of this synthetic form of folate in the American diet. Folic acid in circulation may be a useful measure of physiologic exposure to synthetic folic acid, and there is a potential for elevated co...

311

Acid placement and coverage in the acid jetting process  

E-print Network

Many open-hole acid treatments are being conducted by pumping acid through jetting ports placed at the end of coiled tubing or drill pipe. The filter-cake on the bore-hole is broken by the jet; the acid-soluble material is dissolved, creating...

Mikhailov, Miroslav I.

2009-05-15

312

Acid Placement in Acid Jetting Treatments in Long Horizontal Wells  

E-print Network

In the Middle East, extended reach horizontal wells (on the order of 25,000 feet of horizontal displacement) are commonly acid stimulated by jetting acid out of drill pipe. The acid is jetted onto the face of the openhole wellbore as the drill pipe...

Sasongko, Hari

2012-07-16

313

College Chemistry Students' Mental Models of Acids and Acid Strength  

ERIC Educational Resources Information Center

The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research…

McClary, LaKeisha; Talanquer, Vicente

2011-01-01

314

Acid Earth--The Global Threat of Acid Pollution.  

ERIC Educational Resources Information Center

Acid pollution is a major international problem, but the debate it has elicited has often clouded the distinction between myth and facts. This publication attempts to concerning the acid pollution situation. This publication attempts to identify available facts. It is the first global review of the problem of acid pollution and the first to…

McCormick, John

315

Determination of organic compounds in bottled waters  

Microsoft Academic Search

The presence of organic compounds in bottled waters available in the Greek market and their fate when the representative samples exposed at different conditions were the main purposes of this study. The determination of the organic compounds was performed by gas chromatography–mass spectrometry techniques. Disinfection by-products compounds, such as trihalomethanes (THMs) and haloacetic acids (HAAs), were detected at low concentrations

Stavroula V. Leivadara; Anastasia D. Nikolaou; Themistokles D. Lekkas

2008-01-01

316

REGULATED DRINKING WATER CONTAMINANTS: NEUROTOXIC PROPERTIES  

EPA Science Inventory

The most common classes of the disinfection by-products (DBPs) encountered in chlorinated systems are regulated with average annual limits for total trihalomethanes (80 µg/liter) and a sum of five of the haloacetic acids (60 µg/liter). Questions persist regarding noncancer health...

317

The impact of variable hydraulic operation of water distribution networks on disinfection by-product concentrations  

Microsoft Academic Search

This study assessed the magnitude of variations in the concentrations of disinfection by-products, specifically trihalomethanes and haloacetic acids, which occur in two UK water distribution networks of different sizes due to changes in the hydraulic operation of the networks. These operational changes included varying the fill levels of water storage tanks and pumping conditions within the network. This was investigated

Emesomake Idornigie; Michael R. Templeton; Cedo Maksimovic; Suzan Sharifan

2010-01-01

318

COAGULATION  

EPA Science Inventory

This chapter reports on the efforts of the USEPA to study conventional and enhanced coagulation for the control of disinfection by-products (DBPs) in drinking water. It examines the control of DBPs like trihalomethanes, haloacetic acids and the surrogate total organic halide in t...

319

BACTERIALLY-MEDIATED DEGRADATION OF A CHIRAL DISINFECTION BYPRODUCT  

EPA Science Inventory

Disinfection of drinking and waste waters, through chlorination, can result in the production of chlorinated organic compounds, many of which are regulated by the U.S. Environmental Protection Agency. Among these regulated compounds are the haloacetic acids, which exhibit toxic e...

320

Use of Normal Human Colon Cells to Assess Toxicities of Unregulated Disinfection By-products and Mixtures  

EPA Science Inventory

The discovery of chlorination and chloramination by-products other than the regulated trihalomethanes and haloacetic acids has created a need for short-term in vitro assays to address toxicities that might be associated with human exposure. Approximately 600 disinfection by-produ...

321

DBP FORMATION KINETICS IN A SIMULATED DISTRIBUTION SYSTEM  

EPA Science Inventory

Little is known about how the growth of halogenated disinfection by-products (DBPs) in drinking water is affected by time spent in a distribution system. Experiments were performed to compare the rate of trihalomethane and haloacetic acid production in a simulated pipe environmen...

322

Reducing Disinfection By-Products in Small Drinking Water Systems  

E-print Network

Reducing Disinfection By-Products in Small Drinking Water Systems by M. Robin Collins, James P + Disinfectant = DBPs NOM=Natural Organic Matter=Organic Precursor Disinfectants=Chlorine, Chloramination, UV, Ozone, Chlorine Dioxide DBPs=Disinfection By-Products Trihalomethanes (THMs), 80 ug/L Haloacetic Acids

323

UV and UV\\/H2O2 Treatment: The Silver Bullet for By-product and Genotoxicity Formation in Water Production  

Microsoft Academic Search

Since Rook showed the production of trihalomethanes by drinking water chlorination, reaction product formation by chemical disinfection\\/oxidation has been thoroughly investigated. Originally, the focus was on the formation of individual organic products. After chlorination, trihalomethanes (THMs), haloacetic acids (HAAs) and many other halogenated compounds were found. After ozonation, ultraviolet (UV) disinfection and advanced oxidation, biodegradable organic by-products such as carboxylic

A. J. Martijn; J. C. Kruithof

2012-01-01

324

Application of oxidative removal of NOM to drinking water and formation of disinfection by-products  

Microsoft Academic Search

Water samples of different origins (Buyukcekmece and Omerli, Istanbul, Turkey, and Alento, Salerno, Italy) were treated by coagulation, ozonation, and coagulation followed by ozonation and photocatalysis. Disinfection by-products (DBPs) formation potential of raw and treated water samples was compared in relation to removal efficiencies by the respective treatment methods. The major DBPs, namely trihalomethanes (THMs) and haloacetic acids (HAAs), and

M. Bekbolet; C. S. Uyguner; H. Selcuk; L. Rizzo; A. D. Nikolaou; S. Meriç; V. Belgiorno

2005-01-01

325

Formation of disinfection by-products in indoor swimming pool water: The contribution from filling water natural organic matter and swimmer body fluids  

Microsoft Academic Search

The contribution and role of different precursors in the formation of three class of disinfection by-products (DBPs) [trihalomethanes (THMs), haloacetic acids (HAAs), and halonitromethanes (HNMs)] in swimming pool waters were examined using filling waters obtained from five drinking water treatment plant (WTP) effluents and three body fluid analogs (BFAs). BFAs exerted higher chlorine demands as compared to natural organic matter

Amer Kanan; Tanju Karanfil

2011-01-01

326

Molecular Structure of Maleic acid  

NSDL National Science Digital Library

Maleic acid is colorless to white crystals with a faint acidulous odor and a characteristic repulsive, astringent taste. Maleic acid is used in making polyesters, surface coatings, lubricant additives, agricultural chemicals and paint vehicles. It is used in organic synthesis of fumaric acid, succinic, aspartic, tartaric, propionic, lactic, malonic, acrylic and hydrocarylic acids. Maleic acid and its anhydride are prepared industrially by the catalytic oxidation of benzene. Maleic acid may be released into waste water during its production and used in the manufacture of polymer products. Dust of maleic acid is irritating to the eyes, nose and throat. The general population is exposed to maleic acid in areas with heavy traffic since it is found in aerosols from auto exhaust.

2004-11-10

327

Molecular Structure of Glutaric acid  

NSDL National Science Digital Library

Glutaric acid is a colorless liquid and white crystals as a solid occurring in plants and animal tissues. It is used in organic synthesis and as an intermediate for the manufacture of polymers such as polyamides and polyesters, ester plasticizers and corrosion inhibitors. It is also useful in the application of decreasing polymer elasticity and in a variety of industrial applications. In addition glutaric acid plays an important role as an intermediary in the Krebs cycle and is used in medication against a large number of viruses and in animal diabetes. Glutaric acid can be prepared from cyclopentanone by oxidative ring fission with nitric acid and in the presence of a catalyst. Glutaric acid has the lowest melting point among dicarboxylic acids (98 C); it is very soluble in water and the solution in water is a medium strong acid. Short-term exposure to glutaric acid may cause irritation to the eyes, skin and the respiratory tract.

2004-11-10

328

Pantothenic acid (Vitamin B5)  

MedlinePLUS

Pantothenic acid is a vitamin, also known as vitamin B5. It is widely found in both plants and animals ... Vitamin B5 is commercially available as D-pantothenic acid, as well as dexpanthenol and calcium pantothenate, which ...

329

Molecular Structure of Sulfuric Acid  

NSDL National Science Digital Library

H2SO4 was discovered by alchemists and made from heating a compound of iron sulfate. In 1740, sulfuric acid was produced for commercial sale. Sulfuric acid is a very strong acid which is used in car batteries. The acid disassociates in water to give two protons and sulfate. This acid can destroy flesh and cause blindness. It was discovered in the 19th century that adding sulfuric acid to soil produces phosphorus, which is beneficial to plants; hence, sulfuric acid is used as a fertilizer in the form of super phosphate and ammonium sulfate. Sulfuric acid is also used to refine petroleum and process metals, and is found in paints and car batteries.

2002-08-15

330

Omega-3 fatty acids (image)  

MedlinePLUS

Omega-3 fatty acids are a form of polyunsaturated fat that the body derives from food. Omega-3s (and omega-6s) are known as essential fatty acids (EFAs) because they are important for good health. ...

331

Acid rain: Reign of controversy  

SciTech Connect

Acid Rain is a primer on the science and politics of acid rain. Several introductory chapters describe in simple terms the relevant principles of water chemistry, soil chemistry, and plant physiology and discuss the demonstrated or postulated effects of acid rain on fresh waters and forests as well as on statuary and other exposed objects. There follow discussions on the economic and social implications of acid rain (for example, possible health effects) and on the sources, transport, and distribution of air pollutants.

Kahan, A.M.

1986-01-01

332

Molecular Structure of Octanoic acid  

NSDL National Science Digital Library

Caprylic acid is a colorless oil manufactured from 1-heptene or 1-octanol. Octanoic acid has an unpleasant rancid taste. When converted from the carboxlic acid to an ester, it has a pleasant taste. In addition, esters of caprylic acid are used in the preparation of dyes, perfumes, and food preservatives. This compound has also been found to have antifungal activity and is used to treat yeast infections.

2002-10-11

333

Molecular Structure of Trimesic acid  

NSDL National Science Digital Library

Trimesic Acid is made up of a benzene ring with three carboxylic groups at the 1, 3, and 5 positions, and it can be synthesized from the oxidation of 1,3,5-trimethyl benzene. The acid is an important building block in crystal engineering which is used to form honeycomb structures, but it has the ability to form diverse supramolecular structures. Also, trimesic acid salt and the free trimesic acid are useful as a plasticizer.

2003-05-08

334

Molecular Structure of Acetic acid  

NSDL National Science Digital Library

Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

2003-06-02

335

Enviropedia: Introduction to Acid Rain  

NSDL National Science Digital Library

This resource provides information about acid rain, a widespread term used to describe all forms of acid precipitation. The sources, nature, and chemistry of acid rain are discussed, along with its impact on buildings, soils, freshwater lakes, trees, and wildlife. Other topics include measuring, modeling, and monitoring acid rain; and vehicle and industrial emission controls. The problem of airborne pollutants migrating across international borders is also discussed.

336

Acid rain abatement  

SciTech Connect

This patent describes a method of obtaining acid rain abatement from a flue gas containing nitrogen oxides (NOX) and sulfur oxides (SOX). It comprises the steps of treating the flue gas with a reducing agent to remove the remaining oxygen and produce an effluent, the reducing agent being selected from group consisting of natural gas, methane, a mixture of CO and hydrogen derived from steam, hydrocarbon, and hydrogen, passing effluent over a catalyst to simultaneously reduce the NOX to water and elemental nitrogen and the SOX to H{sub 2}S or elemental sulfur, the catalyst being selected from the group consisting of heteropoly acids and their salts, the reduction of the NOX and SOX taking place in a temperature range of 200{degrees} - 900{degrees} C., and removing the sulfur or sulfur compounds from the reduced flue gas to thereby remove essentially all of the NOX and SOX.

Stiles, A.B.

1991-06-11

337

Acid hydrolysis of cellulose  

SciTech Connect

One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

Salazar, H.

1980-12-01

338

Industrial ecotoxicology "acid rain".  

PubMed

The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent. PMID:3758667

Astolfi, E; Gotelli, C; Higa, J

1986-01-01

339

A ACID RAIN Audrey Gibson  

E-print Network

A ACID RAIN Audrey Gibson ATOC 3500 Thursday, April 29, 2010 #12;CAUSES Natural sources - volcanoes Thursday, April 29, 2010 #12;ON WILDLIFE Acid rain causes acidification of lakes and streams and contributes to damage of trees at high elevations. Acid rain primarily affects sensitive bodies of water

Toohey, Darin W.

340

An Umbrella for Acid Rain.  

ERIC Educational Resources Information Center

The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

Randal, Judith

1979-01-01

341

Synthesis of Acetylsalicylic Acid (Aspirin)  

Microsoft Academic Search

The purpose of this experiment was to synthesize acetylsalicylic acid via an esterification reaction between salicylic acid and acetic anhydride. The product was recrystallized using 95% ethanol. This percent yield of this synthesized product was 68.4%. Using ethanol again as a recrystallizing solvent, acetylsalicylic acid was also extracted from commercial aspirin tablets. This commercial product did not have a percent

Jamie Yeadon; Leah Monroe

342

Do We Need Gastric Acid?  

Microsoft Academic Search

Evidence from comparative anatomy and physiology studies indicates that gastric acid secretion developed during the evolution of vertebrates approximately 350 million years ago. The cellular mechanisms that produce gastric acid have been conserved over the millennia and therefore proton pump inhibitors have pharmacological effects in almost all relevant species. These observations suggest that gastric acid provides an important selective advantage;

D. Pohl; M. Fox; M. Fried; B. Göke; C. Prinz; H. Mönnikes; G. Rogler; M. Dauer; J. Keller; F. Lippl; I. Schiefke; U. Seidler; H. D. Allescher

2008-01-01

343

Pantothenic acid biosynthesis in zymomonas  

DOEpatents

Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

2014-07-01

344

New politics of acid rain  

SciTech Connect

The acid rain problem is not nationwide across the USA but the politicians want to spread the cost of emission reductions. An overview of acid rain and its environmental impacts is given, and a cost-benefit analysis of acid rain control is outlined. USA policies are discussed. 6 references.

Trisko, E.M.

1983-07-01

345

Molecular Structure of Carbonic acid  

NSDL National Science Digital Library

The hypothetical acid formed with carbon dioxide and water; it is only in the H2CO3 form when in solution. This acid is found in everyday products, the most prominent of which include carbonated beverages. The conversion of carbonic acid into water and carbon dioxide in sodas is the reason the beverage looses the bubbling.

2002-09-10

346

Carboxylic acid sorption regeneration process  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine. 10 figs.

King, C.J.; Poole, L.J.

1995-05-02

347

Biotechnological production of pyruvic acid  

Microsoft Academic Search

Pyruvic acid is an important organic acid widely used in the chemical and drug, as well as agrochemical, industries. Compared with the chemical method, biotechnological production of pyruvic acid is an alternative approach because of the low cost. An overview of biotechnological production of pyruvate, including direct fermentative production employing eukaryotic and prokaryotic microorganisms, production by a resting cell method

Y. Li; J. Chen; S.-Y. Lun

2001-01-01

348

Nucleic Acids Molecular Biology Tools  

E-print Network

Nucleic Acids Proteins Molecular Biology Tools Molecular Biology and Genomics Weigang Qiu Weigang Qiu Molecular Biology and Genomics #12;Nucleic Acids Proteins Molecular Biology Tools Outline 1 Nucleic Acids 2 Proteins 3 Molecular Biology Tools Weigang Qiu Molecular Biology and Genomics #12;Nucleic

Qiu, Weigang

349

Acid rain in Asia  

Microsoft Academic Search

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to\\u000a the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging\\u000a perception that the problem in these Western nations is nearing solution. The situation in

Neeloo Bhatti; David G. Streets; Wesley K. Foell

1992-01-01

350

Acid Rain Effects  

NSDL National Science Digital Library

Learners conduct a simple experiment to model and explore the harmful effects of acid rain (vinegar) on living (green leaf and eggshell) and non-living (paper clip) objects. Learners observe the effects over a period of days. This activity has links to other activities which can be combined to make a larger lesson. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.

Amy Kolenbrander

2004-01-01

351

Iron amino acid chelates.  

PubMed

Iron amino acid chelates, such as iron glycinate chelates, have been developed to be used as food fortificants and therapeutic agents in the prevention and treatment of iron deficiency anemia. Ferrous bis-glycine chelate (FeBC), ferric tris-glycine chelate, ferric glycinate, and ferrous bis-glycinate hydrochloride are available commercially. FeBC is the most studied and used form. Iron absorption from FeBC is affected by enhancers and inhibitors of iron absorption, but to a lesser extent than ferrous sulfate. Its absorption is regulated by iron stores. FeBC is better absorbed from milk, wheat, whole maize flour, and precooked corn flour than is ferrous sulfate. Supplementation trials have demonstrated that FeBC is efficacious in treating iron deficiency anemia. Consumption of FeBC-fortified liquid milk, dairy products, wheat rolls, and multi-nutrient beverages is associated with an improvement of iron status. The main limitations to the widespread use of FeBC in national fortification programs are the cost and the potential for promoting organoleptic changes in some food matrices. Additional research is required to establish the bioavailability of FeBC in different food matrices. Other amino acid chelates should also be evaluated. Finally there is an urgent need for more rigorous efficacy trials designed to define the relative merits of amino acid chelates when compared with bioavailable iron salts such as ferrous sulfate and ferrous fumarate and to determine appropriate fortification levels PMID:15743019

Hertrampf, Eva; Olivares, Manuel

2004-11-01

352

Exposures to acidic aerosols  

SciTech Connect

Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m/sup 3/ more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H+ determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr H+ concentrations exceeded 550 nmole/m/sup 3/ (approximately 27 micrograms/m/sup 3/ H/sub 2/SO/sub 4/). The maximum estimated 1-hr concentration exceeded 1500 nmole/m/sup 3/ for H+ ions. At these concentrations, an active child might receive more than 2000 nmole of H+ ion in 12 hr and in excess of 900 nmole during the hour when H/sub 2/SO/sub 4/ exceeded 50 micrograms/m/sup 3/.

Spengler, J.D.; Keeler, G.J.; Koutrakis, P.; Ryan, P.B.; Raizenne, M.; Franklin, C.A.

1989-02-01

353

Exposures to acidic aerosols  

SciTech Connect

Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H(+) ion concentrations exceeding 100 nmole/cu m more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H(+) determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr (H+) concentrations exceeded 550 nmole/cu m (approximately 27 microgram/cu m H{sub 2}SO{sub 4}). The maximum estimated 1-hr concentration exceeded 1500 nmole/cu m for H(+) ions. At these concentrations, an active child might receive more than 2000 nmole of H(+) ion in 12 hr and in excess of 900 nmole during the hour when H{sub 2}SO{sub 4} exceeded 50 microgram/cu m.

Spengler, J.D.; Keeler, G.J.; Koutrakis, P.; Ryan, P.B.; Raizenne, M.

1989-01-01

354

Evolution of rosmarinic acid biosynthesis.  

PubMed

Rosmarinic acid and chlorogenic acid are caffeic acid esters widely found in the plant kingdom and presumably accumulated as defense compounds. In a survey, more than 240 plant species have been screened for the presence of rosmarinic and chlorogenic acids. Several rosmarinic acid-containing species have been detected. The rosmarinic acid accumulation in species of the Marantaceae has not been known before. Rosmarinic acid is found in hornworts, in the fern family Blechnaceae and in species of several orders of mono- and dicotyledonous angiosperms. The biosyntheses of caffeoylshikimate, chlorogenic acid and rosmarinic acid use 4-coumaroyl-CoA from the general phenylpropanoid pathway as hydroxycinnamoyl donor. The hydroxycinnamoyl acceptor substrate comes from the shikimate pathway: shikimic acid, quinic acid and hydroxyphenyllactic acid derived from l-tyrosine. Similar steps are involved in the biosyntheses of rosmarinic, chlorogenic and caffeoylshikimic acids: the transfer of the 4-coumaroyl moiety to an acceptor molecule by a hydroxycinnamoyltransferase from the BAHD acyltransferase family and the meta-hydroxylation of the 4-coumaroyl moiety in the ester by a cytochrome P450 monooxygenase from the CYP98A family. The hydroxycinnamoyltransferases as well as the meta-hydroxylases show high sequence similarities and thus seem to be closely related. The hydroxycinnamoyltransferase and CYP98A14 from Coleus blumei (Lamiaceae) are nevertheless specific for substrates involved in RA biosynthesis showing an evolutionary diversification in phenolic ester metabolism. Our current view is that only a few enzymes had to be "invented" for rosmarinic acid biosynthesis probably on the basis of genes needed for the formation of chlorogenic and caffeoylshikimic acid while further biosynthetic steps might have been recruited from phenylpropanoid metabolism, tocopherol/plastoquinone biosynthesis and photorespiration. PMID:19560175

Petersen, Maike; Abdullah, Yana; Benner, Johannes; Eberle, David; Gehlen, Katja; Hücherig, Stephanie; Janiak, Verena; Kim, Kyung Hee; Sander, Marion; Weitzel, Corinna; Wolters, Stefan

2009-01-01

355

Composition for nucleic acid sequencing  

DOEpatents

The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

Korlach, Jonas (Ithaca, NY); Webb, Watt W. (Ithaca, NY); Levene, Michael (Ithaca, NY); Turner, Stephen (Ithaca, NY); Craighead, Harold G. (Ithaca, NY); Foquet, Mathieu (Ithaca, NY)

2008-08-26

356

Invasive cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

2002-01-01

357

Invasive cleavage of nucleic acids  

DOEpatents

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

1999-01-01

358

The politics of acid rain  

SciTech Connect

This work examines and compares the acid rain policies through the different political systems of Canada, Great Britain and the United States. Because the flow of acid rain can transcend national boundaries, acid rain has become a crucial international problem. According to the author, because of differences in governmental institutions and structure, the extent of governmental intervention in the industrial economy, the degree of reliance on coal for power generation, and the extent of acid rain damage, national responses to the acid rain problem have varied.

Wilcher, M.E. (Pennsylvania State Univ., New Kensington, PA (US))

1989-01-01

359

Acid precipitation: causes and consequences  

SciTech Connect

Acid precipitation has been associated with industrial and automotive emissions of sulfur oxides - principally sulfur dioxide and, to a lesser extent, sulfur trioxide - and nitric oxide and nitrogen oxide. All forms of fossil fuel combustion, particularly that produced by the internal combustion engines emit nitrogen oxides. In addition, smelters and coal-fired electric power plants are the primary source of sulfur oxides. Since U.S. coals may also contain as much as 0.65 percent chlorine, hydrochloric acid plays a minor role in acid precipitation. In addition to the causes of acid precipitation, long distant transport of these pollutants is discussed along with the environmental impacts of acid precipitation. (JMT)

Babich, H. (Environmental Law Inst., Washington, DC); Davis, D.L.; Stotzky, G.

1980-05-01

360

Molecular Structure of Benzoic acid  

NSDL National Science Digital Library

Benzoic acid is a medium-strong acid found in human foods such as berries, and is used as a plasticizer, insecticide, fungicide, an antifungal agent and in the manufacture of pharmaceuticals. It is more hydrophobic, water fearing, in comparison with other carboxylic acids and therefore can be extracted easily from all types of solvents. This acid is slightly soluble in water and has a melting point of 122 degrees Celsius. Benzoic acid is industrially manufactured from toluene, benzotrichloride and phthalic anhydride. It is purified by the process of sublimation, and the extremely pure form is used as a titrimetric and calorimetric standard in analytical chemistry.

2003-05-08

361

Molecular Structure of Adipic acid  

NSDL National Science Digital Library

Adipic acid is odorless and colorless white crystals or powder with a sour taste. Adipic acid is used primarily in the manufacture of nylon-6,6 polyamide and polyester polyols for polyurethane systems. It is also used for raw materials in pharmaceuticals, perfume fixatives, acidulants, leavening and buffering agents in non-alcoholic beverages, gelatins and puddings. In addition, adipic acid is used in manufacturing plasticizers and lubricants components. It is slightly soluble in water and soluble in alcohol and acetone. Adipic acid can be prepared from acetylene and acetic acid in the presence of tert-butyl peroxide. It has been manufactured from either cyclohexane or phenol.

2004-11-09

362

Acid Rain Experiments: Soil Buffering  

NSDL National Science Digital Library

This experiment will help students understand that soil sometimes contains substances, like limestone, that buffer acids or bases, and that some salts in soil may also act as buffers. They will collect soil samples from their lawn, garden, or school and look for buffering effects by observing the pH change of an acid mixture poured through the samples. If the water collected from the sample is less acidic than the original mixture, then the soil is buffering some of the acid. If it does not change, then the soil may not be capable of buffering acids.

363

Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.  

ERIC Educational Resources Information Center

Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

Raw, C. J. G.; And Others

1983-01-01

364

Amino acids in Arctic aerosols  

NASA Astrophysics Data System (ADS)

Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids and quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 ?m) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions.

Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

2012-11-01

365

Amino acids in Arctic aerosols  

NASA Astrophysics Data System (ADS)

Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids to quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (<0.49 ?m) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanics.

Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

2012-07-01

366

Molecular Structure of Picric acid  

NSDL National Science Digital Library

Picric Acid was first discovered in 1771 by a British Chemist named Peter Woulfe by treatment of indigo with nitric acid. It is most commonly seen in its yellow, water-soluble, crystalline form. For this reason, picric acid first saw use as a dyeing agent in textiles. However, around 1849 it was discovered (for obvious reasons) that picric acid is a shock, heat, and friction-sensitive explosive. Its first use as an explosive material came in military weaponry: torpedoes in particular due to its shock-sensitive nature not requiring a detonator to explode on contact with a target. However, picric acid was found to be highly corrosive to metals, making the weapons very difficult to handle and the acid itself difficult to store. Today, picric acid is used more widely as an ingredient in the manufacture of inert dyes and stable explosives such as dynamite.

2002-09-23

367

Molecular Structure of Sorbic acid  

NSDL National Science Digital Library

Sorbic acid is a colorless or white crystalline powder, with a weak characteristic odor and slightly acidic taste. It may be obtained from berries of the mountain ash or prepared synthetically by condensing crotonaldehyde and malonic acid in pyridine solution. Sorbic acid is a polyunsaturated fat used to inhibit molds and yeast, is a fungistatic agent for foods (especially cheeses, wine and baked goods). The main use of sorbic acid is as a preservative in foods, animal feeds, tobacco, cosmetics and pharmaceuticals, as well in packing materials for these substances and in other products that come in contact with human or animal skin in some way. Sorbic acid is also used as an intermediate for plasticizers and lubricants. Sorbic acid reacts with potassium to make potassium sorbate and with calcium to make calcium sorbate.

2004-11-11

368

Citric Acid, Pyruvic Acid, Homologs, and Related Compounds in Carbonaceous Meteorites  

NASA Astrophysics Data System (ADS)

We report three new classes of meteoritic organic compounds: keto acids, hydroxy tricarboxylic acids, and tricarboxylic acids. Some of the compounds, such as pyruvic acid and citric acid, are at the core of intermediary metabolism.

Cooper, G.; Reed, C.; Nguyen, D.; Carter, M.; Wang, Y.

2011-03-01

369

21 CFR 184.1061 - Lactic acid.  

Code of Federal Regulations, 2012 CFR

... Lactic acid. (a) Lactic acid (C3 H6 O3 , CAS...chemical 2-hydroxypropanoic acid, occurs naturally in...commercially either by fermentation of carbohydrates such...subsequent hydrolysis to lactic acid. (b)...

2012-04-01

370

21 CFR 184.1007 - Aconitic acid.  

Code of Federal Regulations, 2011 CFR

...1,2,3-propenetricarboxylic acid (C6 H6 O6 ), CAS Reg...other Ranunculaceae. Transaconitic acid can be isolated during sugarcane...molasses. It may be synthesized by sulfuric acid dehydration of citric acid,...

2011-04-01

371

21 CFR 184.1007 - Aconitic acid.  

Code of Federal Regulations, 2012 CFR

...1,2,3-propenetricarboxylic acid (C6 H6 O6 ), CAS Reg...other Ranunculaceae. Transaconitic acid can be isolated during sugarcane...molasses. It may be synthesized by sulfuric acid dehydration of citric acid,...

2012-04-01

372

21 CFR 184.1007 - Aconitic acid.  

Code of Federal Regulations, 2014 CFR

...1,2,3-propenetricarboxylic acid (C6 H6 O6 ), CAS Reg...other Ranunculaceae. Transaconitic acid can be isolated during sugarcane...molasses. It may be synthesized by sulfuric acid dehydration of citric acid,...

2014-04-01

373

21 CFR 184.1097 - Tannic acid.  

Code of Federal Regulations, 2010 CFR

...Substances Affirmed as GRAS § 184.1097 Tannic acid. (a) Tannic acid (CAS Reg. No. 1401-55-4), or hydrolyzable...complex polyphenolic organic structure that yields gallic acid and either glucose or quinic acid as...

2010-04-01

374

Increased formation of ursodeoxycholic acid in patients treated with chenodeoxycholic acid.  

PubMed Central

The formation of ursodeoxycholic acid, the 7 beta-hydroxy epimer of chenodeoxycholic acid, was investigated in three subjects with cerebrotendinous xanthomatosis and in four subjects with gallstones. Total biliary bile acid composition was analyzed by gas-liquid chromatography before and after 4 months of treatment with 0.75 g/day of chenodeoxycholic acid. Individual bile acids were identified by mass spectrometry. Before treatment, bile from cerebrotendinous xanthomatosis (CTX) subjects contained cholic acid, 85%; chenodeoxycholic acid, 7%; deoxycholic acid, 3%; allocholic acid, 3%; and unidentified steroids, 2%; while bile from gallstone subjects contained cholic acid, 45%; chenodeoxycholic acid, 43%; deoxycholic acid, 11%, and lithocholic acid, 1%. In all subjects, 4 months of chenodeoxycholic acid therapy increased the proportion of this bile acid to approximately 80% and decreased cholic acid to 3% of the total biliary bile acids, the remaining 17% of bile acids were identified as ursodeoxycholic acid. After the intravenous injection of [3H]chenodeoxycholic acid, the specific activity of biliary ursodeoxycholic acid exceeded the specific activity of chenodeoxycholic acid, and the resulting specific activity decay curves suggested precursor-product relationships. When [3H]7-ketolithocholic acid was administrated to another patient treated with chenodeoxycholic acid, radioactivity was detected in both the ursodeoxycholic acid and chenodeoxycholic acid fractions. These results indicate that substantial amounts of ursodeoxycholic acid are formed in patients treated with chenodeoxycholic acid. The ursodeoxycholic acid was synthesized from chenodeoxycholic acid presumably via 7-ketolithocholic acid. Images PMID:11344576

Salen, G; Tint, G S; Eliav, B; Deering, N; Mosbach, E H

1974-01-01

375

Vibrational structure of the polyunsaturated fatty acids eicosapentaenoic acid and arachidonic acid studied by infrared spectroscopy  

NASA Astrophysics Data System (ADS)

The spectroscopic discrimination of the two structurally similar polyunsaturated C 20 fatty acids (PUFAs) 5,8,11,14,17-eicosapentaenoic acid and 5,8,11,14-eicosatetraenoic acid (arachidonic acid) is shown. For this purpose their vibrational structures are studied by means of attenuated total reflection (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The fingerprint regions of the recorded spectra are found to be almost identical, while the C-H stretching mode regions around 3000 cm -1 show such significant differences as results of electronic and molecular structure alterations based on the different degree of saturation that both fatty acids can be clearly distinguished from each other.

Kiefer, Johannes; Noack, Kristina; Bartelmess, Juergen; Walter, Christian; Dörnenburg, Heike; Leipertz, Alfred

2010-02-01

376

Corals on Acid  

NSDL National Science Digital Library

The objective of this inquiry-based lesson is for learners to gain an understanding of how increasing ocean acidity can affect the calcification of marine organisms. During this activity, learners: (1) design an experiment to quantify the CaCO3 concentration of two invertebrate skeletal samples, one that has been soaked in normal seawater and another in a low pH solution, and (2) use critical thinking and discussion to evaluate possible explanations for the difference in the skeletal CaCO3 compositions. This lesson plan includes a post-activity demonstration, which shows how the dissolution of CO2 into the ocean lowers pH.

Casey L. Boleman

2013-01-01

377

GROUP SELECTIVITY OF ETHOXYLATION OF HYDROXY ACIDS  

Microsoft Academic Search

A study of the ethoxylation of two hydroxy acids was undertaken to determine if there was any group selectivity of ethoxylation. The hydroxy acids chosen for study were 12-hydroxystearic and lactic acid. Standard ethoxylation reactions were carried out using one mole of ethylene oxide to one mole of each hydroxy acid. Unlike typical fatty acids or alcohols, 12- hydroxystearic acid

Anthony J. O'Lenick; JEFF K. PARKINSON

378

Background on Net Acid or ARD Potential  

E-print Network

acid generating and the amount of acid is determined by titration and expressed in the same units01-1 Background on Net Acid or ARD Potential GARD Guide Section 5.4.10 Types of Tests · Acid Base Accounting (ABA) ­ Measures net acid potential through independent determination of acid generating

Boisvert, Jeff

379

Growth of nitric acid hydrates on thin sulfuric acid films  

NASA Technical Reports Server (NTRS)

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

1994-01-01

380

Growth of nitric acid hydrates on thin sulfuric acid films  

SciTech Connect

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 [times] 10[sup [minus]4] Torr H[sub 2]O and 1-2.5 [times] 10[sup [minus]6] Torr HNO[sub 3]) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO[sub 3]/H[sub 2]O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H[sub 2]SO[sub 4] films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

Iraci, L.T.; Middlebrook, A.M.; Wilson, M.A.; Tolbert, M.A. (Univ. of Colorado, Boulder, CO (United States))

1994-05-15

381

Electrolytic nature of aqueous sulfuric acid. 2. Acidity.  

PubMed

In part 1 of this study, I reported that the Debye-Hückel limiting law and the smaller-ion shell (SiS) model of strong electrolyte solutions fit nicely with the experimental mean ionic activity coefficient (?(±)) of aqueous sulfuric acid as a function of concentration and of temperature when the acid is assumed to be a strong 1-3 electrolyte. Here, I report that the SiS-derived activity coefficient of H(+), ?(H(+)), of the 1-3 acid is comparable to that of aqueous HCl. This agrees with titration curves showing, as well-known, that sulfuric acid in water is parallel in strength to aqueous HCl. The calculated pH is in good accord with the Hammett acidity function, H(0), of aqueous sulfuric acid at low concentration, and differences between the two functions at high concentration are discussed and explained. This pH-H(0) relation is consistent with the literature showing that the H(0) of sulfuric acid (in the 1-9 M range) is similar to those of HCl and the other strong mineral monoprotic acids. The titration of aqueous sulfuric acid with NaOH does not agree with the known second dissociation constant of 0.010 23; rather, the constant is found to be ~0.32 and the acid behaves upon neutralization as a strong diprotic acid practically dissociating in one step. A plausible reaction pathway is offered to explain how the acid may transform, upon base neutralization, from a dissociated H(4)SO(5) (as 3H(+) and HSO(5)(3-)) to a dissociated H(2)SO(4) even though the equilibrium constant of the reaction H(+) + HSO(5)(3-) ? SO(4)(2-) + H(2)O, at 25 °C, is 10(-37) (part 1). PMID:22924595

Fraenkel, Dan

2012-09-27

382

Kinetics of aluminum-fulvic acid complexation in acidic waters  

Microsoft Academic Search

A fluorescence technique has been used to study the complex formation kinetics of aluminum with a single metal-free fulvic acid isolated from an Adirondack Mountain forest soil. In the pH range of 3.0-4.5, two kinetically distinguishable components of the fulvic acid mixture have been identified, which define two types of average aluminum binding sites. Both fulvic acid average sites conform

Brian J. Plankey; Howard H. Patterson

1987-01-01

383

Carboxylic Acid Unknowns and Titration 90 CARBOXYLIC ACID UNKNOWN  

E-print Network

, and the hydroxide runs out, you won't get full dissolving. · NaHCO3/H2O: An acid-base reaction should lead to solution, but the other unique thing is that acid-base protonation of bicarbonate leads to CO2 bubbles the # of moles of base used. Since the mole/mole stoichiometry is 1 mole of base per 1 mole of acid

Jasperse, Craig P.

384

Biophysical Properties of Phenyl Succinic Acid Derivatised Hyaluronic Acid  

Microsoft Academic Search

Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared\\u000a to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic\\u000a materials. In the present study, hyaluronic acid has been derivatised with the anhydride form of phenyl succinic acid (PheSA).\\u000a The fluorescence

Maria Teresa Neves-Petersen; Søren Klitgaard; Esben Skovsen; Steffen B. Petersen; Kristoffer Tømmeraas; Khadija Schwach-Abdellaoui

2010-01-01

385

Nucleic Acid Detection Methods  

DOEpatents

The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3'-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated.

Smith, Cassandra L. (Boston, MA); Yaar, Ron (Brookline, MA); Szafranski, Przemyslaw (Boston, MA); Cantor, Charles R. (Boston, MA)

1998-05-19

386

Nucleic acid detection methods  

DOEpatents

The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3{prime}-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated. 18 figs.

Smith, C.L.; Yaar, R.; Szafranski, P.; Cantor, C.R.

1998-05-19

387

Cryoprotection from lipoteichoic acid  

NASA Astrophysics Data System (ADS)

Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, and with a few exceptions, antifreeze proteins are missing. Survival has been attributed to external factors, such as the high salt concentration of brine veins and adhesion to particulates or ice crystal defects. We have discovered an endogenous cryoprotectant in the cell wall of bacteria, lipoteichoic acid biopolymers. Adding 1% LTA to bacteria cultures immediately prior to freezing provides 50% survival rate, similar to the results obtained with 1% glycerol. In the absence of an additive, bacterial survival is negligible as measured with the resazurin cell viability assay. The mode of action for LTA cryoprotection is unknown. With a molecular weight of 3-5 kDa, it is unlikely to enter the cell cytoplasm. Our observations suggest that teichoic acids could provide a shell of liquid water around biofilms and planktonic bacteria, removing the need for brine veins to prevent bacterial freezing.

Rice, Charles V.; Middaugh, Amy; Wickham, Jason R.; Friedline, Anthony; Thomas, Kieth J.; Johnson, Karen; Zachariah, Malcolm; Garimella, Ravindranth

2012-10-01

388

Acid rain degradation of nylon  

SciTech Connect

Acid rain, precipitation with a pH less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid of pH 2.0, 3.0, and 4.4 were exposed to light in an Atlas Xenon-arc fadeometer at 63/sup 0/C and 65% R.H. for up to 640 AATCC Fading Units. The untreated and acid treated nylon fabrics were also exposed to similar temperature and humidity condition without light. Nylon degradation was determined by changes in breaking strength, elongation, molecular weight, color, amino end group concentration (NH/sub 2/) and /sup 13/C NMR spectra. Physical damage was assessed using SEM.

Kyllo, K.E.

1984-01-01

389

Molecular Structure of Phosphoric acid  

NSDL National Science Digital Library

Phosphoric acid was first made in 1774 by K.W. Scheele and J.G. Gahn from bone ash. Phosphoric acid is made by treating calcium phosphate rock with sulfuric acid, followed by filtration. It is by this process that almost 10 tons of phosphoric acid are produced in the United States each year. The compound is primarily used to manufacture some pharmaceutical products, fertilizers and as a flavoring agent in coca-cola. The steel industry uses it to clean and rust-proof their steel. Phosphoric acid is also used in the process of soil stabilization, and as a catalyst in the production of propylene and butene polymers, ethylbenzene, and cumene. In recent years though the industry has moved away from using phosphoric acid as a ingredient in detergents because of the harmful effect that Phosphates have on lakes a process called lake eutrophication.

2002-09-10

390

Molecular Structure of Butyric acid  

NSDL National Science Digital Library

n-Butyric acid is a substance that was isolated from butter in 1869. Butyric acid means, in Latin, the acid of butter as it was first discovered in rancid butter. It is found most commonly in butter, but can also be present in some fruits. Butyric acid is also produced synthetically, through fermentation of various carbohydrates, to be used as a flavoring agent in various food products. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. It is also used for the production of plastics, plasticizers, surfactants and textile auxiliaries. Butyric acid and its derivatives are also being seriously considered around the world as potential anticancer agents.

2002-10-11

391

Molecular Structure of (+-)-Malic acid  

NSDL National Science Digital Library

Malic acid, along with lots of other natural acids, was discovered by Karl Wilhem Scheele. Malic acid is a naturally occurring substance in many fruits and plants, however its richest source is apples, which is why it is sometimes referred to as apple acid . It is blended with multiple food acids, sugars, high intensity sweeteners, flavors, and seasonings to create unique tastes in foods, beverages, and confections. It has also been found that Malic acid may help with reducing the effects of Alzheimer s disease by reducing the levels of aluminum and magnesium in the body. Also, it has been recommended as a supplement for Chronic Fatigue Syndrome, as it is known to improve energy production.

2002-10-10

392

Molecular Structure of Salicylic acid  

NSDL National Science Digital Library

Salicylic acid is a colorless to white crystalline powder with a sweetish acrid taste that occurs naturally in many microorganisms and plants in very small amounts. It is also made synthetically and used as preservative of food products in some countries and as an antiseptic in mouthwashes and toothpastes. This chemical is also used in the manufacture of methyl salicylates, acetylasalicylic acid (aspirin) and other salicylates. Salicylic acid is a chemical intermediate in the synthesis of dyestuff, salicylate esters and salts. It is prepared commercially by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure to form sodium salicylate, which is treated with sulfuric acid to liberate salicylic acid. Salicylic acid is quite irritating to skin and mucosa and it destroys epithelial cells. Absorption of large amounts can cause vomiting, abdominal pain, acidosis and mental disturbances.

2004-11-11

393

Aqueous Ozonation Of Fatty Acids  

Microsoft Academic Search

The reactivity of a series of fatty acids toward ozone was examined in aqueous solution at low substrate concentration (?g.L range). Saturated fatty acids were unreactive, unsaturated fatty acids were readily consumed. A number of reaction products or their methylated derivatives were identified by gas chromatography and gas chromatography-mass spectrometry. The products identified are consistent with a 1,3-dipolar cyclo-addotion reaction.

G. Reynolds; C. Corless; N. Graham; R. Perry; T. M. Gibson; J. Haley

1989-01-01

394

Waste acid detoxification and reclamation  

Microsoft Academic Search

Economically feasible processes that reduce the volume, quantity, and toxicity of metal-bearing waste acids by reclaiming, reusing, and recycling spent acids and metal salts are being developed and demonstrated. The acids used in the demonstrations are generated during metal-finishing operations used in nuclear fuel fabrication; HF-HNOâ, HNOâ, and HNOâ-HâSOâ wastes result from Zr etching, Cu stripping, and chemical milling of

T. M. Brouns; T. L. Stewart

1988-01-01

395

All-trans retinoic acid regulates hepatic bile acid homeostasis.  

PubMed

Retinoic acid (RA) and bile acids share common roles in regulating lipid homeostasis and insulin sensitivity. In addition, the receptor for RA (retinoid x receptor) is a permissive partner of the receptor for bile acids, farnesoid x receptor (FXR/NR1H4). Thus, RA can activate the FXR-mediated pathway as well. The current study was designed to understand the effect of all-trans RA on bile acid homeostasis. Mice were fed an all-trans RA-supplemented diet and the expression of 46 genes that participate in regulating bile acid homeostasis was studied. The data showed that all-trans RA has a profound effect in regulating genes involved in synthesis and transport of bile acids. All-trans RA treatment reduced the gene expression levels of Cyp7a1, Cyp8b1, and Akr1d1, which are involved in bile acid synthesis. All-trans RA also decreased the hepatic mRNA levels of Lrh-1 (Nr5a2) and Hnf4? (Nr2a1), which positively regulate the gene expression of Cyp7a1 and Cyp8b1. Moreover, all-trans RA induced the gene expression levels of negative regulators of bile acid synthesis including hepatic Fgfr4, Fxr, and Shp (Nr0b2) as well as ileal Fgf15. All-trans RA also decreased the expression of Abcb11 and Slc51b, which have a role in bile acid transport. Consistently, all-trans RA reduced hepatic bile acid levels and the ratio of CA/CDCA, as demonstrated by liquid chromatography-mass spectrometry. The data suggest that all-trans RA-induced SHP may contribute to the inhibition of CYP7A1 and CYP8B1, which in turn reduces bile acid synthesis and affects lipid absorption in the gastrointestinal tract. PMID:25175738

Yang, Fan; He, Yuqi; Liu, Hui-Xin; Tsuei, Jessica; Jiang, Xiaoyue; Yang, Li; Wang, Zheng-Tao; Wan, Yu-Jui Yvonne

2014-10-15

396

Molecular Structure of Propionic acid  

NSDL National Science Digital Library

Propanoic acid was named after the Greek word "Pro" for first and "pion" for fat, because it is the first fatty acid. It is a liquid and has a slightly pungent odor that can be characterized as rancid. Sweat, milk, and fermentation products all contain small amounts of this chemical. It can be synthesized from ethanol or ethylene and carbon monoxide. The calcium salt of propanoic acid is used as an antimolding agent and is an additive in breads. Esters of this carboxylic acid have a pleasant smell and taste and are used in the manufacture of fruit flavors and perfume bases. This compound is also found in a herbicide, called Silverado.

2002-10-11

397

Molecular Structure of Lauric acid  

NSDL National Science Digital Library

Lauric acid was first discovered in lauraceae seeds by Marsson T in 1849. The highest content of lauric acid is found in a mother's breast milk and lauraceae seeds. It is used in foods such as vegetable shortenings as a defoaming agent and industrially as a booster for soaps and detergents. Also it is used in cosmetics, insecticides, and food additives. Additionally, Lauric acid is a medium chain fatty acid, which forms monolaurin in the human or animal body. This compound is an antiviral, antibacterial, and antiprotozoal monoglyceride that destroys lipid coated viruses such as HIV, herpes, cytomegalovirus, and influenza.

2002-10-11

398

Acidic gas capture by diamines  

DOEpatents

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

Rochelle, Gary (Austin, TX); Hilliard, Marcus (Missouri City, TX)

2011-05-10

399

A Simpler Nucleic Acid  

NASA Technical Reports Server (NTRS)

It has been supposed that for a nucleic acid analog to pair with RNA it must, like RNA, have a backbone with at least a sixatom repeat; a shorter backbone presumably would not stretch far enough to bind RNA properly. The Eschenmoser group has shown, however, that this first impression is incorrect.As they report in their new paper, Eschenmoser and co-workers ( I ) have now synthesized a substantial number of these polymers, which are called (L)-a-threofuranosyl oligonucleotides or TNAs. They are composed of bases linked to a threose sugar-phosphate backbone, with phosphodiester bonds connecting the nucleotides. The investigators discovered that pairs of complementary TNAs do indeed form stable Watson-Crick double helices and, perhaps more importantly, that TNAs form stable double helices with complementary RNAs and DNAs.

Orgel, Leslie

2000-01-01

400

Acid rain on acid soil: a new perspective  

Microsoft Academic Search

Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has

E. C. Krug; C. R. Frink

1983-01-01

401

Peptidases and amino acid catabolism in lactic acid bacteria  

Microsoft Academic Search

The conversion of peptides to free amino acids and their subsequent utilization is a central metabolic activity in prokaryotes. At least 16 peptidases from lactic acid bacteria (LAB) have been characterized biochemically and\\/or genetically. Among LAB, the peptidase systems of Lactobacillus helveticus and Lactococcus lactis have been examined in greatest detail. While there are homologous enzymes common to both systems,

Jeffrey E. Christensen; Edward G. Dudley; Jeffrey A. Pederson; James L. Steele

1999-01-01

402

No Potassium, No Acid: K+ Channels and Gastric Acid Secretion  

NSDL National Science Digital Library

The gastric H+-K+-ATPase pumps H+ into the lumen and takes up K+ in parallel. In the acid-producing parietal cells, luminal KCNE2/KCNQ1 K+ channels play a pivotal role in replenishing K+ in the luminal fluid. Inactivation of KCNE2/KCNQ1 channels abrogates gastric acid secretion and dramatically modifies the architecture of gastric mucosa.

2007-10-01

403

The acid-base reactions of the ?-hydroxypiperidinecarboxylic acids  

Microsoft Academic Search

1.Ionization constants have been determined for the ß-hydroxypyridinecarboxylic acids and their ethyl esters.2.It has been shown that these acids can exist in various forms in aqueous solution, depending on the pH, and conditions for the transition from one of these forms to another have been marked out.

B. A. Korolev; L. G. Stolyarova; L. D. Smirnov; K. M. Dyumaev

1979-01-01

404

Fatty acid-amino acid conjugates diversification in Lepidopteran caterpillars  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fatty acid amino acid conjugates (FACs) have been found in Noctuid as well as Sphingid caterpillar oral secretions and especially volicitin [N-(17-hydroxylinolenoyl)-L-Glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants...

405

Capturing a sulfenic acid with arylboronic acids and benzoxaborole.  

PubMed

Post-translational redox generation of cysteine-sulfenic acids (Cys-SOH) functions as an important reversible regulatory mechanism for many biological functions, such as signal transduction, balancing cellular redox states, catalysis, and gene transcription. Herein we show that arylboronic acids and cyclic benzoxaboroles can form adducts with sulfenic acids in aqueous medium and that these boron-based compounds can potentially be used to trap biologically significant sulfenic acids. As proof of principle we demonstrate that a benzoxaborole can inhibit the enzyme activity of an iron-containing nitrile hydratase, which requires a catalytic ?Cys114-SOH in the active site. The nature of the adduct and the effect of the boronic acid's pK(a)(B) on the stability constant of the adduct are discussed within. PMID:24050501

Liu, C Tony; Benkovic, Stephen J

2013-10-01

406

A comparison of chromic acid and sulfuric acid anodizing  

NASA Technical Reports Server (NTRS)

Because of federal and state mandates restricting the use of hexavalent chromium, it was deemed worthwhile to compare the corrosion protection afforded 2219-T87 aluminum alloy by both Type I chromic acid and Type II sulfuric acid anodizing per MIL-A-8625. Corrosion measurements were made on large, flat 2219-T87 aluminum alloy sheet material with an area of 1 cm(exp 2) exposed to a corrosive medium of 3.5-percent sodium chloride at pH 5.5. Both ac electrochemical impedance spectroscopy and the dc polarization resistance techniques were employed. The results clearly indicate that the corrosion protection obtained by Type II sulfuric acid anodizing is superior, and no problems should result by substituting Type II sulfuric acid anodizing for Type I chromic acid anodizing.

Danford, M. D.

1992-01-01

407

Docosahexaenoic acid and n-6 docosapentaenoic acid supplementation alter rat skeletal muscle fatty acid composition  

Microsoft Academic Search

BACKGROUND: Docosahexaenoic acid (22:6n-3, DHA) and n-6 docosapentaenoic acid (22:5n-6, DPAn-6) are highly unsaturated fatty acids (HUFA, ? 20 carbons, ? 3 double bonds) that differ by a single carbon-carbon double bond at the ?19 position. Membrane 22:6n-3 may support skeletal muscle function through optimal ion pump activity of sarcoplasmic reticulum and electron transport in the mitochondria. Typically n-3 fatty

Ken D Stark; Sun-Young Lim; Norman Salem Jr

2007-01-01

408

Artificial rearing with docosahexaenoic acid and n-6 docosapentaenoic acid alters rat tissue fatty acid composition  

Microsoft Academic Search

Docosahexaenoic acid (DHA; 22:6n-3) and n-6 docosapentaenoic acid (DPAn-6; 22:5n-6) are components of enriched animal feed and oil derived from Schizochytrium species microalgae. A one generation, artificial rearing model from day 2 after birth onward (AR) and a dam-reared control group (DAM) were used to examine DPAn-6 feeding on the fatty acid composition of various rat tissues at 15 weeks

Ken D. Stark; Sun-Young Lim; Norman Salem

2007-01-01

409

Condensed imidazo-1,2,4-azines 22. Alkylation of 5H-imidazo[1,2-b]-1,2,4-triazepin-4-ones  

Microsoft Academic Search

Substituted 5H-imidazo[1,2-b]-1,2,4-triazepin-4-ones react with alkyl (alkenyl) halides, 2-chloroethanol, glycerin dichlorohydrin, haloacetic acids, the methyl ester and amide of monochloroacetic acid in a methanol-sodium methylate system to form N(5)-alkylation products, and with hydroxylamino-O-sulfonic acid to form 5-aminoimidazo[1,2-b]-1,2,4-triazepin-4-one.

V. P. Kruglenko; V. A. Idzikovskii; N. N. Kobets; M. V. Povstyanoi

1990-01-01

410

Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains  

PubMed Central

A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, ?-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

1988-01-01

411

On the acidity and reactivity of highly effective chiral Brønsted acid catalysts: establishment of an acidity scale.  

PubMed

Stronger acid, higher speed: The pKa ?values of a range of binol-derived Brønsted acids of three different types were measured and found to correlate directly with the catalytic properties of the acids: higher rate constants kI were observed for more acidic Brønsted acid catalysts (see plot; binol=1,1'-bi-2-naphthol). PMID:24039083

Kaupmees, Karl; Tolstoluzhsky, Nikita; Raja, Sadiya; Rueping, Magnus; Leito, Ivo

2013-10-25

412

Synthesis of l-(+)-Tartaric Acid from l-Ascorbic Acid via 5-Keto-d-Gluconic Acid in Grapes  

PubMed Central

5-Keto-l-idionic acid (?5-keto-d-gluconic acid, d-xylo-5-hexulosonic acid) was found as a metabolic product of l-ascorbic acid in slices of immature grapes, Vitis labrusca L. cv `Delaware'. Specifically labeled compounds, recognized as metabolic products of l-ascorbic acid in grapes, were fed to young grape tissues to investigate the metabolic pathway from l-ascorbic acid to l-(+)-tartaric acid. Label from dehydro-l-[1-14C]ascorbic acid, 2-keto-l-[1-14C]idonic acid (l-xylo-2-hexulosonic acid), l-[1-14C]idonic acid, or 5-keto-l-[1-14C] idonic acid was incorporated into l-(+)-tartaric acid in high yields as it was in the l-[1-14C]ascorbic acid experiment. In a double label experiment involving a mixture of l-[1-14C]idonic acid and l-[2-3H]idonic acid, the 3H/14C ratios of 5-keto-l-idonic acid and l-(+)-tartaric acid synthesized in young grape leaves were almost the same as the value of the l-idonic acid fed. Label from 5-keto-l-[6-14C]idonic acid was incorporated into sugars and insoluble residue in the same way as l-[6-14C]ascorbic acid was metabolized in grapes. These results provide strong evidence that in grapes l-(+)-tartaric acid is synthesized from the C4 fragment that corresponds to the C1 to C4 group of the 5-keto-l-idonic acid derived from l-ascorbic acid via 2-keto-l-idonic acid and l-idonic acid. PMID:16663792

Saito, Kazumi; Kasai, Zenzaburo

1984-01-01

413

Acid Tests and Basic Fun.  

ERIC Educational Resources Information Center

Explores acids and bases using different indicators, such as turmeric, purple grape juice, and lichens. Because some of these indicators are not as sensitive as cabbage juice or litmus paper, determining to which acids and bases each indicator is sensitive presents an enjoyable, problem-solving challenge for students. Presents directions for…

McBride, John W.

1995-01-01

414

Acid rain & electric utilities II  

SciTech Connect

This document presents reports which were presented at the Acid Rain and Electric Utilities Conference. Topics include environmental issues and electric utilities; acid rain program overview; global climate change and carbon dioxide; emissions data management; compliance; emissions control; allowance and trading; nitrogen oxides; and assessment. Individual reports have been processed separately for the United States Department of Energy databases.

NONE

1997-12-31

415

Acid Rain: An Educational Opportunity?  

ERIC Educational Resources Information Center

Deals with how educators can handle the subject of acid rain; illustrates suggestions with experiences of grade nine students visiting Frost Valley Environmental Education Center (Oliverea, New York) to learn scientific concepts through observation of outdoor phenomena, including a stream; and discusses acid rain, pH levels, and pollution control…

Marion, James I.

1984-01-01

416

Acid Rain: The Scientific Challenge.  

ERIC Educational Resources Information Center

Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

Godfrey, Paul J.

1991-01-01

417

The Acid Rain Differential Game  

Microsoft Academic Search

This paper considers an acid rain differential game. Countries emit sulphur which is partly transferred to other countries. Depositions above critical loads ultimately destroy the soil. Countries face a trade-off between the costs of emission reductions and the damage to the soil due to the depletion of the acid buffers. Because of the transboundary externalities the outcome will depend on

Karl-Göran Mäler; Aart De Zeeuw

1998-01-01

418

Acid Rain: What's the Forecast?  

ERIC Educational Resources Information Center

Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

Bybee, Rodger

1984-01-01

419

Acid Precipitation: Causes and Consequences.  

ERIC Educational Resources Information Center

This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)

Babich, Harvey; And Others

1980-01-01

420

BOTANICAL ASPECTS OF ACIDIC PRECIPITATION  

EPA Science Inventory

Acidic precipitation can be characterized as wet or frozen atmospheric deposition with a hydrogen ion concentration greater than 2.5 microequivalents liter-1. Acidic precipitation is perceived as a significant air pollution problem derived chiefly from combustion of fossil fuels,...

421

Heteropolysaccharides from lactic acid bacteria  

Microsoft Academic Search

Microbial exopolysaccharides are biothickeners that can be added to a wide variety of food products, where they serve as viscosifying, stabilizing, emulsifying or gelling agents. Numerous exopolysaccharides with different composition, size and structure are synthesized by lactic acid bacteria. The heteropolysaccharides from both mesophilic and thermophilic lactic acid bacteria have received renewed interest recently. Structural analysis combined with rheological studies

Luc De Vuyst; Bart Degeest

1999-01-01

422

ACID DEPOSITION AND FOREST DECLINE  

EPA Science Inventory

The location, topography and other characteristics of the high-elevation forests of eastern North America cause them to be receptors of high levels of acid deposition and airborn trace metals. No other major forested areas in the U.S. are subjected to such intensely acid cloud mo...

423

Acid Secretion and Gastric Surgery  

Microsoft Academic Search

It was long believed that there were major differences in the pathophysiology between the three major categories of peptic ulcers. The unifying feature was that all peptic ulcers occurred in a mucosal compartment exposed to acid-pepsin secretions. All ulcers tended to heal more rapidly when acid secretion was more readily neutralized or inhibited. Decreased local resistance was considered to be

Lars Lundell

2011-01-01

424

Vibrational Spectra of ?-Aminobutyric Acid  

NASA Astrophysics Data System (ADS)

The NIR-FT Raman, FT-IR spectral analysis of ?-Aminobutyric acid (GABA) a simple amino acid is carried out by density functional computations. The vibrational spectra confirm the existence of NH3+ in GABA. Hydroxyl groups H-bonded to the different extents are analysed, supported by computed results.

Suresh, D. M.; Sajan, D.; Laladas, K. P.; Joe, I. Hubert; Jayakumar, V. S.

2008-11-01

425

Molecular Structure of Formic acid  

NSDL National Science Digital Library

Formic Acid, also known as methanoic acid and hydrogencarboxylic acid, is the simplest organic acid. It is a colorless, toxic, corrosive liquid with a pungent, penetrating odor. In nature, it is found in the stings and bites of many insects of the order hymenoptera, including bees and ants. The principal use of formic acid is as a preservative and antibacterial agent in livestock feed. The largest single use of formic acid is as a silage additive in Europe, but this market hardly exists in the United States. When sprayed on fresh hay or other silage, it arrests certain decay processes and causes the feed to retain its nutritive value longer. In the poultry industry, it is sometimes added to silage to kill salmonella bacteria. It is also used in textile dyeing, leather tanning, as a solvent, in electroplating processes, in the manufacturing of lacquers, glass, vinyl resin plasticizers, and formate esters (for flavor and fragrance) and in the manufacture of fumigants. Formic acid is a strong reducing agent, and may act both as an acid and as an aldehyde because the carboxyl is bound to a hydrogen rather than an alkyl group.

2003-05-08

426

Learning About Acids and Bases  

NSDL National Science Digital Library

The chemistry of acids and bases is a fundamental area of study in the physical sciences. The following activity is really two exercises in one. First, students learn to distinguish between acids and bases using various color-changing indicator solutions.

John Eichinger

2009-05-15

427

TRANS ACIDS IN SPECIALTY LIPIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The role of trans acids in human health and nutrition is highly controversial and a search of the Internet reveals the interest in the subject. Trans acids are perceived as "killer fats" at one end of the spectrum to having no adverse effects at the other. In addition, saturated fats are perceived...

428

Amino acid-based surfactants  

Microsoft Academic Search

There is a pressing need for developing efficiently surfactants that are biodegradable and biocompatible. Surfactant molecules from renewable raw materials that mimic natural lipoamino acids are one of the preferred choices for food, pharmaceutical and cosmetic applications. Given their natural and simple structure they show low toxicity and quick biodegradation. The value of amino acids and vegetable oil derivatives as

María Rosa Infante; Lourdes Pérez; Aurora Pinazo; Pere Clapés; María Carmen Morán; Marta Angelet; María Teresa García; María Pilar Vinardell

2004-01-01

429

Metabolism of Lysergic Acid Diethylamide  

Microsoft Academic Search

ALTHOUGH the hallucinogenic agent, lysergic acid diethylamide, has been the subject of numerous investigations, little is known about its biological fate. The development of a specific and sensitive method for the estimation of lysergic acid diethylamide in biological materials has enabled us to study its physiological disposition and metabolism.

Julius Axelrod; Roscoe O. Brady; Bernhard Witkop; Edward V. Evarts

1956-01-01

430

Synthesis of pyromellitic acid esters  

NASA Technical Reports Server (NTRS)

The ester acids necessary for studyng the thermochemical properties of pyromellitic acid (PMK)-based peroxides were investigated. Obtaining a tetramethyl ester of a PMK was described. The mechanism of an esterification reaction is discussed, as is the complete esterification of PMK with primary alcohol.

Fedorova, V. A.; Donchak, V. A.; Martynyuk-Lototskaya, A. N.

1985-01-01

431

Acid Mine Drainage and Precipitates  

NSDL National Science Digital Library

In this video, environmental scientists measure the pH of water to detect acid mine drainage from an abandoned coal mine and then demonstrate how metals present in acid drainage fall out of solution as precipitates when a basic substance is added to the water.

KET

2011-01-11

432

Getting Back to Basics (& Acidics)  

ERIC Educational Resources Information Center

This article describes a few novel acid-base experiments intended to introduce students to the basic concepts of acid-base chemistry and provide practical examples that apply directly to the study of biology and the human body. Important concepts such as the reaction between carbon dioxide and water, buffers and protein denaturation, are covered.…

Rhodes, Sam

2006-01-01

433

Acid dissolution hydrodynamic force analysis  

Microsoft Academic Search

The purpose of this calculation is to analyze the hydrodynamic forces associated with the in-tank piping feeding the tank fluid agitation eductor (sparger), as well as eductor induced forces. These forces will be used as input to the structural analysis of the support structure used for the acid dissolution assembly, and the acid dissolution assembly itself.

2003-01-01

434

Acid dissolution hydrodynamic force analysis  

SciTech Connect

The purpose of this calculation is to analyze the hydrodynamic forces associated with the in-tank piping feeding the tank fluid agitation eductor (sparger), as well as eductor induced forces. These forces will be used as input to the structural analysis of the support structure used for the acid dissolution assembly, and the acid dissolution assembly itself.

WHITE, M.A.

2003-05-21

435

Molecular Structure of Isophthalic acid  

NSDL National Science Digital Library

Isophthalic acid is one of the three simple aromatic dicarboxylic acids with the carboxyl groups in the meta postions. It is used to produce isophthalic polyester that together with other components is used in resin systems for flame retardants and in corrosion prevention.

2008-01-10

436

Solid Acids for Green Chemistry  

Microsoft Academic Search

Solid acids and especially those based on micelle-templated silicas and other mesoporous high surface area support materials are beginning to play a significant role in the greening of fine and speciality chemicals manufacturing processes. A wide range of important organic reactions can be efficiently catalyzed by these materials, which can be designed to provide different types of acidity as well

James H. Clark

2002-01-01

437

SOIL REACTION AND ACIDIC DEPOSITION  

EPA Science Inventory

This chapter discusses the major chemical processes by which acidic deposition interacts with soils. he focus is on forest soils, as the effects of acidic deposition on soils used for production of food and fiber are generally small compared to effects of agricultural practices s...

438

Atmospheric dust and acid rain  

SciTech Connect

Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

Hedin, L.O.; Likens, G.E.

1996-12-01

439

Molecular Structure of Galacturonic acid  

NSDL National Science Digital Library

Galacturonic acid is the monobasic acid resulting from oxidation of the primary alcohol group of D-galactose to carboxyl. It is widely distributed as a constituent of pectins (compounds with heterogeneous grouping of acidic structural polysaccharides, found in fruit and vegetables), many plant gums, and mucilages (gummy substances obtained from certain plants, which are used as food stabilizers). Gums tend to be used as thickening and bulking agents in pharmaceutics, and they play a less obvious part in most plants. Once swallowed, their actions are no different from those of the mucilages. D-Galacturonic acid prepared from pectin can be used to synthesize vitamin C. Native pectin is a mixture of polysaccharides, with the major component a polymer of -D-galacturonic acid. Pectin has numerous other medical and pharmaceutical uses, for example in combination with plant hemicelluloses and lignin, may be useful dietary constituents in preventing coronary heart disease, diverticular disease, ulcerative colitis, and a variety of other Western diseases.

2003-05-08

440

Molecular Structure of Linoleic acid  

NSDL National Science Digital Library

Linoleic acid is a polyunsaturated fatty acid occurring widely in plant glycerides or fats. Common sources include many vegetable oils such as flax seed, safflower, soybean, peanut, and corn; some margarines; and dairy fats. It is a colorless to straw-colored liquid, insoluble in water, but soluble in alcohol and ether. Linoleic acid is easily oxidized by air and is combustible. It also appears as an aluminum salt, in the form of yellow lumps or powder, that is practically insoluble in water but soluble in oils and fixed alkalai hydroxides. Linoleic acid is essential in human nutrition and is used also for soaps, animal feeds, paints, drying protective coatings, emulsifying or smoothing and wetting agents, and in biochemical research. The conjugated form of linoleic acid or CLA has been associated with health benefits such as lowered risk of cancer and atherosclerosis. Prepared CLA is available as a supplement. However, foods high in CLA content could be used.

2003-05-08

441

Molecular Structure of Acroleic acid  

NSDL National Science Digital Library

Acrylic acid is a colorless liquid that has an irritating bitter odor and was discovered by Josef Redtenbacher, a German chemist. This substance is miscible with water and most organic solvents. Known also as 2-propeonic acid, this plant molecule occurs naturally in marine algae and has been found in the rumen fluid of sheep. Acrylic acid has been found to polymerize easily when exposed to heat, light, or metals so, therefore a polymerization inhibitor is added to commercial for storage. The acid is used in the manufacture of plastics, floor polish, paint formulations, leather finishings, and paper coatings. Exposure to the liquid occurs primarily in the workplace and can irritate the skin, eyes, and mucous membranes of humans. Acrylic acid has not been classified as a carcinogen.

2003-05-08

442

Molecular Structure of Stearic acid  

NSDL National Science Digital Library

Stearic acid is white leaflets, slightly yellow crystal masses or a white to slightly yellow powder. Stearic acid is a saturated fatty acid found in low percentages in cotton, coconut, palm kernel, corn, palm, castor, rapeseed, soybean, sunflower, herring, and tallow oils. It is also one of the fat components found in the cocoa butter of chocolate. It is prepared synthetically by hydrogenation of cottonseed and other vegetable oils or by treating animal fat with water at a high pressure and temperature. Stearic acid is useful as an ingredient in making candles, soaps, and for softening synthetic rubber. It is also a component of cosmetic formulations, pharmaceuticals creams and vanishing lotion. Stearic acid is practically nontoxic but the dust is irritating to eyes, nose, and throat and the solid is irritating to skin and eyes.

2004-11-11

443

Fumaric acid production by fermentation  

PubMed Central

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

Roa Engel, Carol A.; Zijlmans, Tiemen W.; van Gulik, Walter M.; van der Wielen, Luuk A. M.

2008-01-01

444

ACID RAIN DEGRADATION OF NYLON (POLYAMIDE, PHOTODEGRADATION)  

Microsoft Academic Search

Acid rain, precipitation with a ph less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid

KAREN E KYLLO

1984-01-01

445

An Abstracting Transformation for Amino Acid Polymorphism  

E-print Network

An Abstracting Transformation for Amino Acid Polymorphism Anthony M. Castaldo, PhD Research three nucleotide se- quences (a codon) into amino acids: Amino Acid (or signal) Codons A (Alanine) GCT believe what is important is the sequence of amino acids produced, and because amino acids average about

Texas at San Antonio, University of

446

The standard amino acids alanine ala A  

E-print Network

The standard amino acids alanine ala A cysteine cys C aspartic acid asp D glutamic acid glu E's the mapping from nucleotide triplets in DNA sequences (via messenger RNA) to individual amino acids, and T) but only 20 amino acids, and that the code is redundant or "degenerate" in the sense that several

Guevara-Vasquez, Fernando

447

21 CFR 186.1316 - Formic acid.  

Code of Federal Regulations, 2013 CFR

...acid. It occurs naturally in some insects and is contained in the free acid state in a number of plants. Formic acid is prepared by the reaction of sodium formate with sulfuric acid and is isolated by distillation. (b) Formic acid is used...

2013-04-01

448

21 CFR 186.1316 - Formic acid.  

Code of Federal Regulations, 2014 CFR

...acid. It occurs naturally in some insects and is contained in the free acid state in a number of plants. Formic acid is prepared by the reaction of sodium formate with sulfuric acid and is isolated by distillation. (b) Formic acid is used...

2014-04-01

449

21 CFR 186.1316 - Formic acid.  

Code of Federal Regulations, 2012 CFR

...acid. It occurs naturally in some insects and is contained in the free acid state in a number of plants. Formic acid is prepared by the reaction of sodium formate with sulfuric acid and is isolated by distillation. (b) Formic acid is used...

2012-04-01

450

21 CFR 186.1316 - Formic acid.  

Code of Federal Regulations, 2010 CFR

...acid. It occurs naturally in some insects and is contained in the free acid state in a number of plants. Formic acid is prepared by the reaction of sodium formate with sulfuric acid and is isolated by distillation. (b) Formic acid is used...

2010-04-01

451

21 CFR 186.1316 - Formic acid.  

Code of Federal Regulations, 2011 CFR

...acid. It occurs naturally in some insects and is contained in the free acid state in a number of plants. Formic acid is prepared by the reaction of sodium formate with sulfuric acid and is isolated by distillation. (b) Formic acid is used...

2011-04-01

452

Kinetics of aluminum-fulvic acid complexation in acidic waters  

SciTech Connect

A fluorescence technique has been used to study the complex formation kinetics of aluminum with a single metal-free fulvic acid isolated from an Adirondack Mountain forest soil. In the pH range of 3.0-4.5, two kinetically distinguishable components of the fulvic acid mixture have been identified, which define two types of average aluminum binding sites. Both fulvic acid average sites conform to a bidentate chelating binding site kinetic analysis, from which rate and equilibrium parameters have been obtained. From comparison of rate and equilibrium constants of aluminum-salicyclic acid complexation, the authors conclude that the faster reacting component of fulvic acid probably contains salicyclic acid type aluminum binding sites. Results are also compared with those of an aluminum-fluoride kinetic study. Fulvic acid and fluoride react with aluminum by the same mechanism and therefore have the same pH dependence. The dependence of the rate on temperature is, however, quite different for the two reactions. The environmental implications of these findings are discussed. 45 references, 5 figures, 6 tables.

Plankey, B.J.; Patterson, H.H.

1987-06-01

453

Formation of acrylic acid from lactic acid in supercritical water  

SciTech Connect

Supercritical (SC) water is an unusual medium in which fast and specific heterolytic reactions can be conducted at temperatures as high as 400{degree}C. In supercritical water, lactic acid decomposes into gaseous and liquid products via three primary reaction pathways. Products of the acid-catalyzed heterolytic decarbonylation pathway are carbon monoxide, water, and acetaldehyde. Products of the homolytic, decarboxylation pathway are carbon dioxide, hydrogen, and acetaldehyde. Products of the heterolytic, dehydration pathway are acrylic acid and water. The intramolecular nucleophilic displacement of the {alpha}-hydroxyl by the carbonyl group of lactic acid, producing {alpha}-propiolactone as an unstable intermediate which subsequently rearranges to become the unsaturated acid, is a likely mechanism for acrylic acid formation, although an intramolecular E2 elimination initiated by attack of the carbonyl oxygen on a methyl hydrogen cannot be ruled out. Support for the former mechanism comes in part from the observed 100% relative yield of acrylic acid from {beta}-propiolactone in SC water.

Mok, W.S.L.; Antal, M.J. Jr. (Univ. of Hawaii, Honolulu (USA)); Jones, M. Jr. (Princeton Univ., NJ (USA))

1989-09-15

454

Effect of Conjugated Linoleic Acid or Oleic Acid Addition on Fatty Acid Composition Profiles of Poultry Meat  

E-print Network

Two different studies were conducted to reduce the overall amount of omega-6 fatty acids in broiler chickens. The first experiment was performed to determine the effects of dietary conjugated linoleic acid (CLA) and omega-3 fatty acid combination...

Shin, Dae Keun

2011-08-08

455

21 CFR 172.345 - Folic acid (folacin).  

Code of Federal Regulations, 2011 CFR

...acid (folacin). Folic acid (CAS Reg. No. 59-30-3...conditions: (a) Folic acid is the chemical N ...amino]benzoyl]-L -glutamic acid. (b) Folic acid...acid may be added, at levels not to exceed 400...

2011-04-01

456

40 CFR 180.550 - Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues. 180.550 Section... Specific Tolerances § 180.550 Arsanilic acid [(4-aminophenyl) arsonic acid];...

2011-07-01

457

40 CFR 721.2086 - Coco acid triamine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Coco acid triamine condensate, polycarboxylic acid salts. 721.2086 Section 721.2086 Protection...Specific Chemical Substances § 721.2086 Coco acid triamine condensate, polycarboxylic acid...

2011-07-01

458

78 FR 55644 - Styrene, Copolymers with Acrylic Acid and/or Methacrylic Acid; Tolerance Exemption  

Federal Register 2010, 2011, 2012, 2013, 2014

...FRL-9396-9] Styrene, Copolymers with Acrylic Acid and/or Methacrylic Acid; Tolerance Exemption AGENCY: Environmental Protection...for residues of styrene, copolymers with acrylic acid and/or methacrylic acid, with none and/or...

2013-09-11

459

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Fatty acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 Protection...Specific Chemical Substances § 721.3620 Fatty acid amine condensate, polycarboxylic acid...

2010-07-01

460

40 CFR 180.550 - Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Arsanilic acid [(4-aminophenyl) arsonic acid]; tolerances for residues. 180.550 Section... Specific Tolerances § 180.550 Arsanilic acid [(4-aminophenyl) arsonic acid];...

2010-07-01

461

40 CFR 721.2086 - Coco acid triamine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Coco acid triamine condensate, polycarboxylic acid salts. 721.2086 Section 721.2086 Protection...Specific Chemical Substances § 721.2086 Coco acid triamine condensate, polycarboxylic acid...

2010-07-01

462

Carbonic acid on Mars?  

NASA Astrophysics Data System (ADS)

For a long time carbonic acid (H 2CO 3) had defied many efforts for its detection by IR spectroscopic techniques. Recently H 2CO 3 has been synthesized at low temperature (?10-80 K), and stabilized up to ?250 K, by energetic ion irradiation of frozen targets made of H 2O:CO 2 ice mixtures (Moore and Khanna, Spectrochim. Acta47, 255-262, 1991; Moore et al., J, Geophys. Res.96(2), 17,541-17,545, 1991, DelloRusso et al., Geophys. Res.98(E3), 5505-5510, 1993; Brucato et al., Icarus 1996 (in press)) and by protonation of bicarbonate (Hage et al., J. Am. Chem. Soc.115, 8427-8431, 1993; J. Chem. Soc. Faraday Trans.91(17), 2823-2826, 1995). Its IR spectrum has been obtained. A comparison between the IR laboratory spectrum of H 2CO 3 with some spectra of Mars suggests that carbonic could be present on the surface and/or atmosphere of the red planet. Its firm identification requires the acquisition of better astronomical data possibly from space missions (e.g. Mars 96) and would be of primary relevance for both the organic and inorganic chemistry taking place on Mars.

Strazzulla, G.; Brucato, J. R.; Cimino, G.; Palumbo, M. E.

1996-11-01

463

Lead-acid battery  

NASA Technical Reports Server (NTRS)

A light weight lead-acid battery (30) having a positive terminal (36) and a negative terminal (34) and including one or more cells or grid stacks having a plurality of vertically stacked conductive monoplates (10, 20) with positive active material and negative active material deposited on alternating plates in the cell or grid stack. Electrolyte layers (26, 28) positioned between each monoplate are included to provide a battery cell having four sides which is capable of being electrically charged and discharged. Two vertical positive bus bars (42, 43) are provided on opposite sides of the battery cell for connecting the monoplates (10) with positive active material together in parallel current conducting relation. In addition, two negative bus bars (38, 39) on opposite sides of the battery cell each being adjacent the positive bus bars are provided for connecting the monoplates (20) with negative active material together in parallel current conducting relation. The positive (42, 43) and negative (38, 39) bus bars not only provide a low resistance method for connecting the plurality of conductive monoplates of their respective battery terminals (36, 34) but also provides support and structural strength to the battery cell structure. In addition, horizontal orientation of monoplates (10, 20) is provided in a vertical stacking arrangement to reduce electrolyte stratification and short circuiting due to flaking of positive and negative active materials from the monoplates.

Rowlette, John J. (Inventor)

1983-01-01

464

DETERMINATION OF BENZOIC ACID AND SALICYLIC ACID IN COMMERCIAL BENZOIC AND SALICYLIC ACIDS OINTMENTS BY SPECTROPHOTOMETRIC METHOD  

Microsoft Academic Search

Commercial benzoic acid and salicylic acid ointments have been analyzed for benzoic acid and salicylic acid content by using a spectrophotometric method. Since benzoic acid and salicylic acid exhibit overlapping spectra, absorbance measurements are made at two wavelengths, i.e. 271 nm and 303 nm in ethanol (96%v\\/v) for simultaneous determination of the two compounds. The method is direct and involves

IQBAL AHMAD; FAIYAZ HM VAID

465

Nonprotein Amino Acids from Spark Discharges and Their Comparison with the Murchison Meteorite Amino Acids  

PubMed Central

All the nonprotein amino acids found in the Murchison meteorite are products of the action of electric discharge on a mixture of methane, nitrogen, and water with traces of ammonia. These amino acids include ?-amino-n-butyric acid, ?-aminoisobutyric acid, norvaline, isovaline, pipecolic acid, ?-alanine, ?-amino-n-butyric acid, ?-aminoisobutyric acid, ?-aminobutyric acid, sarcosine, N-ethylglycine, and N-methylalanine. In addition, norleucine, alloisoleucine, N-propylglycine, N-isopropylglycine, N-methyl-?-alanine, N-ethyl-?-alanine ?,?-diaminopropionic acid, isoserine, ?,?-diaminobutyric acid, and ?-hydroxy-?-aminobutyric acid are produced by the electric discharge, but have not been found in the meteorite. PMID:16591973

Wolman, Yecheskel; Haverland, William J.; Miller, Stanley L.

1972-01-01

466

Microbial oxidation of oleic acid.  

PubMed Central

Resting cells of Saccharomyces cerevisiae (baker's yeast, type II; Sigma) were used to convert oleic acid into 10-hydroxyoctadecanoic acid with a 45% yield. Nocardia aurantia (ATCC 12674), Nocardia sp. (NRRL 5646), and Mycobacterium fortuitum (UI 53378) all converted oleic acid into 10-oxo-octadecanoic acid with 65, 55, and 80% yields, respectively. Structures of all metabolites were suggested by 1H and 13C nuclear magnetic resonance and by infrared and mass spectrometry. Structures of isomeric hydroxystearate and oxostearate derivatives and the stereochemical purity of hydroxystearates are difficult to prove unambiguously unless authentic standard compounds are available for spectral comparison. We describe the use of the chemical Baeyer-Villiger oxidation technique with 10-oxo-octadecanoic acid followed by mass spectral analysis of neutral extracts as a simple method to confirm the position of oxo-functional groups in the structures of fatty acid ketones. We further introduce a simple method based on 1H nuclear magnetic resonance analysis of diastereomeric S-(+)-O-acetylmandelate esters of hydroxystearates as a means of ascertaining stereochemical purities of hydroxy fatty acids. PMID:1637152

el-Sharkawy, S H; Yang, W; Dostal, L; Rosazza, J P

1992-01-01

467

Phytic acid in green leaves.  

PubMed

Phytic acid or phytate, the free-acid form of myo-inositolhexakiphosphate, is abundant in many seeds and fruits, where it represents the major storage form of phosphorus. Although also known from other plant tissues, available reports on the occurrence of phytic acid, e.g. in leaves, have never been compiled, nor have they been critically reviewed. We found 45 published studies with information on phytic acid content in leaves. Phytic acid was almost always detected when studies specifically tried to detect it, and accounted for up to 98% of total P. However, we argue that such extreme values, which rival findings from storage organs, are dubious and probably result from measurement errors. Excluding these high values from further quantitative analysis, foliar phytic acid-P averaged 2.3 mg·g(-1) , and represented, on average, 7.6% of total P. Remarkably, the ratio of phytic acid-P to total P did not increase with total P, we even detected a negative correlation of the two variables within one species, Manihot esculenta. This enigmatic finding warrants further attention. PMID:24341824

Hadi Alkarawi, H; Zotz, G

2014-07-01

468

Terahertz spectrum of gallic acid  

NASA Astrophysics Data System (ADS)

Gallic acid is natural polyphenol compound found in many green plants. More and more experiments have demonstrated that the gallic acid has comprehensive applications. In the field of medicine, the gallic acid plays an important role in antianaphylaxis, antineoplastic, antimycotic, anti-inflammatory, antivirotic, antiasthmatic and inhibiting the degradation of insulin. It also has a lot of applications in chemical industry, food industry and light industry. So it is important to study the terahertz time-domain spectroscopy of gallic acid. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technology based on the femtosecond laser. In this work, the spectral characteristics of gallic acid in the range of 0.4 THz to 2.6 THz have been measured by THz-TDS. We obtained its absorption and refraction spectra at room temperature. The vibration absorption spectrum of the single molecule between 0.4 THz and 2.6 THz is simulated based on the Density Functional Theory (DFT). It is found that the gallic acid has the spectral response to THz wave in this frequency range. The results show the abnormal dispersion at 1.51 THz and 2.05 THz. These results can be used in the qualitative analysis of gallic acid and the medicine and food inspection.

Wu, Meng; Zhao, Guozhong; Wang, Haiyan; Liang, Chengshen

2009-11-01

469

40 CFR 417.140 - Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...  

Code of Federal Regulations, 2012 CFR

...description of the neutralization of sulfuric acid esters and sulfonic acids subcategory...SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory...description of the neutralization of sulfuric acid esters and sulfonic acids...

2012-07-01

470

40 CFR 417.140 - Applicability; description of the neutralization of sulfuric acid esters and sulfonic acids...  

Code of Federal Regulations, 2013 CFR

...description of the neutralization of sulfuric acid esters and sulfonic acids subcategory...SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory...description of the neutralization of sulfuric acid esters and sulfonic acids...

2013-07-01

471

Molar extinction coefficients of some fatty acids  

NASA Astrophysics Data System (ADS)

The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

2002-10-01

472

21 CFR 582.5013 - Ascorbic acid.  

Code of Federal Regulations, 2010 CFR

...GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be free hydrochloride salt, hydrated, or anhydrous form,...

2010-04-01

473

21 CFR 582.5013 - Ascorbic acid.  

Code of Federal Regulations, 2014 CFR

...GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be free hydrochloride salt, hydrated, or anhydrous form,...

2014-04-01

474

21 CFR 582.5013 - Ascorbic acid.  

Code of Federal Regulations, 2013 CFR

...GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be free hydrochloride salt, hydrated, or anhydrous form,...

2013-04-01

475

21 CFR 582.5013 - Ascorbic acid.  

Code of Federal Regulations, 2012 CFR

...GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be free hydrochloride salt, hydrated, or anhydrous form,...

2012-04-01

476

21 CFR 582.5013 - Ascorbic acid.  

Code of Federal Regulations, 2011 CFR

...GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids listed in this subpart may be free hydrochloride salt, hydrated, or anhydrous form,...

2011-04-01

477

Genetics Home Reference: Sialic acid storage disease  

MedlinePLUS

... Recent literature OMIM Genetic disorder catalog Conditions > Sialic acid storage disease On this page: Description Genetic changes ... Glossary definitions Reviewed February 2008 What is sialic acid storage disease? Sialic acid storage disease is an ...

478

21 CFR 186.1093 - Sulfamic acid.  

Code of Federal Regulations, 2011 CFR

...Substances Affirmed as GRAS § 186.1093 Sulfamic acid. (a) Sulfamic acid (H3 NO3 S, CAS Reg. No. 5329-14-6...solid manufactured from urea, sulfur trioxide, and sulfuric acid. It is soluble and highly ionized in...

2011-04-01

479

21 CFR 186.1093 - Sulfamic acid.  

Code of Federal Regulations, 2010 CFR

...Substances Affirmed as GRAS § 186.1093 Sulfamic acid. (a) Sulfamic acid (H3 NO3 S, CAS Reg. No. 5329-14-6...solid manufactured from urea, sulfur trioxide, and sulfuric acid. It is soluble and highly ionized in...

2010-04-01

480

21 CFR 186.1093 - Sulfamic acid.  

Code of Federal Regulations, 2014 CFR

...Substances Affirmed as GRAS § 186.1093 Sulfamic acid. (a) Sulfamic acid (H3 NO3 S, CAS Reg. No. 5329-14-6...solid manufactured from urea, sulfur trioxide, and sulfuric acid. It is soluble and highly ionized in...

2014-04-01

481

21 CFR 186.1093 - Sulfamic acid.  

Code of Federal Regulations, 2013 CFR

...Substances Affirmed as GRAS § 186.1093 Sulfamic acid. (a) Sulfamic acid (H3 NO3 S, CAS Reg. No. 5329-14-6...solid manufactured from urea, sulfur trioxide, and sulfuric acid. It is soluble and highly ionized in...

2013-04-01

482

21 CFR 186.1093 - Sulfamic acid.  

Code of Federal Regulations, 2012 CFR

...Substances Affirmed as GRAS § 186.1093 Sulfamic acid. (a) Sulfamic acid (H3 NO3 S, CAS Reg. No. 5329-14-6...solid manufactured from urea, sulfur trioxide, and sulfuric acid. It is soluble and highly ionized in...

2012-04-01

483

Nucleic Acid Chaperone Activity of HIV1  

E-print Network

Nucleic Acid Chaperone Activity of HIV1 Nucleocapsid Protein: Critical Role in Reverse ............................................................................ 218 II. Structure and Nucleic Acid Binding Properties of HIV1 NC ........................................................................... 219 A. Specific and Nonspecific Nucleic Acid Binding .............................. 220 B. Structural

Levin, Judith G.

484

Renal handling of terephthalic acid  

SciTech Connect

By use of the Sperber in vivo chicken preparation method, infusion of radiolabeled terephthalic acid ((/sup 14/C)TPA) into the renal portal circulation revealed a first-pass excretion of the unchanged compound into the urine. This model was utilized further to characterize the excretory transport of (/sup 14/C)TPA and provide information on the structural specificity in the secretion of dicarboxylic acids. At an infusion rate of 0.4 nmol/min. 60% of the (/sup 14/C)TPA which reached the kidney was directly excreted. An infusion rate of 3 or 6 mumol/min resulted in complete removal of (/sup 14/C)TPA by the kidney. These results indicate that TPA is both actively secreted and actively reabsorbed when infused at 0.4 nmol/min and that active reabsorption is saturated with the infusion of TPA at higher concentrations. The secretory process was saturated with the infusion of TPA at 40 mumol/mn. The excretory transport of TPA was inhibited by the infusion of probenecid, salicylate, and m-hydroxybenzoic acid, indicating that these organic acids share the same organic anion excretory transport process. m-Hydroxybenzoic acid did not alter the simultaneously measured excretory transport of p-aminohippuric acid (PAH), suggesting that there are different systems involved in the secretion of TPA and PAH. The structural specificity for renal secretion of dicarboxylic acids was revealed by the use of o-phthalic acid and m-phthalic acid as possible inhibitors of TPA secretion.

Tremaine, L.M.; Quebbemann, A.J.

1985-01-01

485

Pyroligneous acid-the smoky acidic liquid from plant biomass.  

PubMed

Pyroligneous acid (PA) is a complex highly oxygenated aqueous liquid fraction obtained by the condensation of pyrolysis vapors, which result from the thermochemical breakdown or pyrolysis of plant biomass components such as cellulose, hemicellulose, and lignin. PA produced by the slow pyrolysis of plant biomass is a yellowish brown or dark brown liquid with acidic pH and usually comprises a complex mixture of guaiacols, catechols, syringols, phenols, vanillins, furans, pyrans, carboxaldehydes, hydroxyketones, sugars, alkyl aryl ethers, nitrogenated derivatives, alcohols, acetic acid, and other carboxylic acids. The phenolic components, namely guaiacol, alkyl guaiacols, syringol, and alkyl syringols, contribute to the smoky odor of PA. PA finds application in diverse areas, as antioxidant, antimicrobial, antiinflammatory, plant growth stimulator, coagulant for natural rubber, and termiticidal and pesticidal agent; is a source for valuable chemicals; and imparts a smoky flavor for food. PMID:25467926

Mathew, Sindhu; Zakaria, Zainul Akmar

2015-01-01

486

Langmuir 1985,1,725-740 725 Acid-Base Behavior of Carboxylic Acid Groups Covalently  

E-print Network

using chromic acid/sulfuric acid introduces a high density of covalently attached carboxylic acid groupsLangmuir 1985,1,725-740 725 Acid-Base Behavior of Carboxylic Acid Groups Covalently Attached: August 7, 1985 Oxidation of polyethylene with chromic acidfsulfuric acid generates a material (PE-C02H

Deutch, John

487

Microwave-Assisted Esterification of Diverse Carboxylic Acids and Chiral Amino Acids  

Microsoft Academic Search

A facile and efficient synthetic method of esters from their corresponding carboxylic acids and amino acids is described. The esterification reaction of carboxylic acids and amino acids could be greatly accelerated under microwave irradiation because the reactions described in this article took place in only 5 min with almost quantitative yields, and distinct acidity of catalytic acids was well tolerated. Unlike

Qian Yang; Xiao-jian Wang; Zhi-yu Li; Li Sun; Qi-dong You

2008-01-01

488

EQUILIBRIUM DISTRIBUTION OF URANYL NITRATE AND NITRIC ACID IN EXTRACTION WITH METHYLCYCLOHEXANONE FROM ACID SOLUTION  

Microsoft Academic Search

The mutual effects of uranyl nitrate and nitric acid on their extraction ; from acid solution with methylcyclohexanone were investigated. The distribution ; of the nitric acid alone for acid concentrations from 0.1 to 4M was first ; determined. The distribution of uranyl nitrate and nitric acid for uranyl ; concentration up to 2M and nitric acid concentrations of 0.1,

F. Havlicek; V. Sraier

1963-01-01

489

Treatment of acid mine wastewaters  

SciTech Connect

Acid mine drainage often results from the oxidation sulfide minerals to form sulfuric acid. As a consequence, high concentrations of metals in the both the suspended and dissolved state result from the low pH water. This paper discusses several of the more common treatment methods for acid mine drainage including the use of chemical precipitation agents, pH correction agents, filtration methods, and biodegradation methods. Advanced treatment technologies are also briefly described and include microfiltration, reverse osmosis, ion exchange, and electrodialysis.

Hayward, D.; Barnard, R.

1993-06-01

490

Be an acid rain detective  

SciTech Connect

Acid rain is discussed in a question and answer format. The article is aimed at educating sport fishermen on the subject, and also to encourage them to write their congressmen, senators, and the President about the acid rain problem. The article also announces the availability of an acid rain test kit available through the magazine, ''Sports Afield.'' The kit consists of pH-test paper that turns different shades of pink and blue according to the pH of the water tested. The color of the test paper is then compared to a color chart furnished in the kit and an approximate pH can be determined.

Atwill, L.

1982-07-01

491

Amino Acids from a Comet  

NASA Technical Reports Server (NTRS)

NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

Cook, Jamie Elisla

2009-01-01

492

Chemiluminescent measurement of atmospheric acid  

NASA Technical Reports Server (NTRS)

The design and construction of a gas phase acid sensitive analyzer are reported. These studies showed that the chemical system was a practical analytical method. A complete instrument was developed and prepared for field testing. A Titan 3-C rocket was scheduled for launching on February 11, 1974. Through preparations made by NASA Langley the instrument was set up to monitor the acid concentration in the rocket exhaust. Due to adverse wind conditions no acid was detected. This entire trip is described in detail.

Stedman, D. H.; Kok, G. L.

1974-01-01

493

Free acidity measurement - a review.  

PubMed

Free acidity is an important parameter especially in the presence of hydrolysable ions. Several methods have been developed for the determination of free acidity, attributing due importance to the accuracy and the precision of the measurement with the aim of the easiness of the methodology as well as post-measurement recovery in mind. This review covers important methods for the determination of free acidity with emphasis on actinide containing solutions, reported in the literature over the past several decades classifying them into different categories. PMID:24274284

Srinivasan, T G; Vasudeva Rao, P R

2014-01-01

494

Environmental Protection Agency: Acid Rain  

NSDL National Science Digital Library

This is the U. S. Environmental Protection Agency's (EPA) acid rain portal. It consists of links to information on the causes and effects of acid rain, how it is measured, and some suggestions for ways to reduce its occurrence. There are also links to information for users about the problem in their areas, and to a selection of educational resources, including activities and science experiments, for students in all grades. Another set of links provides access to information on state and national data and statistics, acid rain legislation, and U.S. and international initiatives.

495

Growth of nitric acid hydrates on thin sulfuric acid films  

Microsoft Academic Search

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 [times] 10[sup [minus]4] Torr H[sub 2]O and 1-2.5 [times] 10[sup [minus]6] Torr HNO[sub 3]) and subjected to cooling and heating cycles. FTIR spectroscopy was used to

Laura T. Iraci; Ann M. Middlebrook; Margaret A. Wilson; Margaret A. Tolbert

1994-01-01

496

Acid–base titration curves of solid humic acids  

Microsoft Academic Search

A direct discontinuous titration method with NaOH was developed to characterize the acid–base properties of complex natural polyelectrolytes, such as humic substances (HS). The classical batch procedure, suggested originally for examinations of resin-based ion exchanger, was modified to be applicable to HS; the modified method is suitable especially for the measurements of the titration curves of solid humic acids (HA).

Pavel Janoš; Sylvie K?íženecká; Libuše Madronová

2008-01-01

497

Quantitative Paper Partition Chromatography of Sialic Acids  

Microsoft Academic Search

RECENTLY, it has been obvious that in most biological materials N-acetylsialic acid (N-acetyl-neuraminic acid) and N-glycolloylsialic acid occur together. By the introduction of a micromethod for the determination of glycollic acid, Klenk and Uhlenbruck1 have made possible the evaluation of the amount of N-glycolloylsialic acid in isolated sialic acids. In search of a more direct method, we tried partition chromatography,

Elisabet Svennerholm; Lars Svennerholm

1958-01-01

498

Nucleic acid arrays and methods of synthesis  

DOEpatents

The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

Sabanayagam, Chandran R. (Allston, MA); Sano, Takeshi (Needham, MA); Misasi, John (Syracuse, NY); Hatch, Anson (Seattle, WA); Cantor, Charles (Del Mar, CA)

2001-01-01

499

Oligomer distribution in concentrated lactic acid solutions  

Microsoft Academic Search

Lactic acid (2-hydroxypropanoic acid) is a significant platform chemical for the biorenewable economy. Concentrated aqueous solutions of lactic acid (>30wt.%) contain a distribution of oligomers that arise via intermolecular esterification. As a result, the titratable acidity changes non-linearly with acid concentration. In this work, the oligomer distribution of lactic acid is characterized using GC, GC\\/MS, and HPLC to extend existing

Dung T. Vu; Aspi K. Kolah; Navinchandra S. Asthana; Lars Peereboom; Carl T. Lira; Dennis J. Miller

2005-01-01

500

Monocarboxylic acid transport.  

PubMed

Monocarboxylates such as lactate, pyruvate, and the ketone bodies play major roles in metabolism and must be transported across both the plasma membrane and mitochondrial inner membrane. A family of five proton-linked MonoCarboxylate Transporters (MCTs) is involved in the former and the mitochondrial pyruvate carrier (MPC) mediates the latter. In the intestine and kidney, two Sodium-coupled MonoCarboxylate Transporters (SMCTs) provide active transport of monocarboxylates across the apical membrane of the epithelial cells with MCTs on the basolateral membrane transporting the accumulated monocarboxylate into the blood. The kinetics and substrate and inhibitor specificities of MCTs, SMCTs, and the MPC have been well characterized and the molecular identity of the MCTs and SMCTs defined unequivocally. The identity of the MPC is less certain. The MCTs have been extensively studied and the three-dimensional structure of MCT1 has been modeled and a likely catalytic mechanism proposed. MCTs require the binding of a single transmembrane glycoprotein (either embigin or basigin) for activity. Regulation of MCT activity involves both transcriptional and posttranscriptional mechanisms, examples being upregulation of MCT1 by chronic exercise in red muscle (which oxidizes lactate) and in T-lymphocytes upon stimulation. MCT4 has properties that make it especially suited for lactic acid export by glycolytic cells and is upregulated by hypoxia. Some disease states are associated with modulation of plasma membrane and mitochondrial monocarboxylate transport and MCTs are promising drug targets for cancer chemotherapy. They may also be involved in drug uptake from the intestine and subsequent transport across the blood brain barrier. PMID:24265240

Halestrap, Andrew P

2013-10-01